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Kosmos
Astronomia Astrofizyka
Inne

Kultura
Sztuka dawna i współczesna, muzea i kolekcje

Metoda
Metodologia nauk, Matematyka, Filozofia, Miary i wagi, Pomiary

Materia
Substancje, reakcje, energia
Fizyka, chemia i inżynieria materiałowa

Człowiek
Antropologia kulturowa Socjologia Psychologia Zdrowie i medycyna

Wizje
Przewidywania Kosmologia Religie Ideologia Polityka

Ziemia
Geologia, geofizyka, geochemia, środowisko przyrodnicze

Życie
Biologia, biologia molekularna i genetyka

Cyberprzestrzeń
Technologia cyberprzestrzeni, cyberkultura, media i komunikacja

Działalność
Wiadomości | Gospodarka, biznes, zarządzanie, ekonomia

Technologie
Budownictwo, energetyka, transport, wytwarzanie, technologie informacyjne

Natural Hazards and Earth System Sciences (NHESS)

Meteorological effects in the lower ionosphere as based on VLF/LF signal observationsNatural Hazards and Earth System Science, 14, 2671-2679, 2014Author(s): A. Rozhnoi, M. Solovieva, B. Levin, M. Hayakawa, and V. FedunVery low and low frequency (VLF/LF) data recorded in the Far Eastern stations
Petropavlovsk-Kamchatsky (158.92° E, 53.15° N),
Yuzhno-Sakhalinsk (142.75° E, 46.95° N) and Yuzhno-Kurilsk
(145.861° E, 44.03° N) are investigated to study the
meteorological effects in the lower ionosphere. The results demonstrate the
sensitivity of the VLF/LF signals to the variations of atmospheric pressure,
humidity, wind velocity and temperature, and the VLF/LF record at the station
of Yuzhno-Kurilsk is found to be most sensitive to those variations of
atmospheric parameters. The region under consideration is characterized by
high winter cyclonic activity in mid-latitudes and strong summer and autumn
typhoon activity in low latitudes. VLF/LF signal variations during eight
tropical cyclones (TCs) with different intensity are considered. Negative
nighttime anomalies in the signal amplitude that are most probably caused by
TC activity are found for six events. Those anomalies are observed during
1–2 days when TCs move inside the sensitivity zones of the subionospheric
paths. Perturbations of the VLF signal observed during two TCs can be caused
by both the TC influence and seismic activity, but no correlation between TC
intensity and magnitude of the signal anomalies is found. Spectral analysis
of the typhoon-induced disturbed signals revealed the fluctuations with time
periods in the range of 7–16 and 15–55 min that corresponds to the range
of internal gravity waves periods.

http://www.nat-hazards-earth-syst-sci.net/14/2671/2014/ 2014/10/01 - 23:30

Methodology for flood frequency estimations in small catchmentsNatural Hazards and Earth System Science, 14, 2655-2669, 2014Author(s): V. David and T. DavidovaEstimations of flood frequencies in small catchments are difficult due to a
lack of measured discharge data. This problem is usually solved in the Czech
Republic by hydrologic modelling when there is a reason not to use the data
provided by the Czech hydrometeorological institute, which are quite
expensive and have a very low level of accuracy. Another way is to use a
simple method which provides sufficient estimates of flood frequency based on
the available spatial data. A new methodology is being developed considering
all important factors affecting flood formation in small catchments. The
relationship between catchment descriptors and flood characteristics has been
analysed first to get an overview of the importance of each considered
descriptor. The results for different descriptors vary from a highly
correlated relationship of an expected shape to a relationship which is
opposite to that expected, mainly in the case of land use. The
parameterisation of the methodology is also presented, including the
sensitivity tests on each involved catchment descriptor and cross-validation
of achieved results. In its present form, the methodology achieves an
Radj2 value of about 0.61 for 10- and 0.60 for 100-year return
periods.

http://www.nat-hazards-earth-syst-sci.net/14/2655/2014/ 2014/10/01 - 23:30

Brief Communication: The interaction of clouds with surface latent heat flux variation before the 2011 M = 6.1 Russia earthquakeNatural Hazards and Earth System Science, 14, 2649-2653, 2014Author(s): Y. Jie and G. GuangmengRecently, surface
latent heat flux (SLHF) data have been widely used to study the anomalies
before earthquakes. Most studies use the daily SLHF data. Here we use both
the daily SLHF data and the high temporal resolution (four times one day)
SLHF data, and compare the SLHF changes with satellite cloud images at the
first time. We check the data from 1 September to 30 October 2011, and the
result shows that there is really a very high SLHF anomaly (more than
2σ) in the epicenter area just 5 days before the M = 6.1 Russia
earthquake that occurred on 14 October 2011. It should be considered as a
preseismic precursor if judged with previously published methods,
but our comparison
between SLHF change and satellite images shows that the SLHF anomaly is
contaminated by a thick cloud. It is difficult to verify that this SLHF
anomaly is caused by an earthquake and our analysis shows that it is more
related to meteorological reason. This example tells us that scientists must
know the data's meaning before they use it; if not, they may draw a wrong
conclusion. Based on this example, we suggest that previously published SLHF
anomalies before earthquakes should be reanalyzed with our method to exclude
the false anomalies.

http://www.nat-hazards-earth-syst-sci.net/14/2649/2014/ 2014/10/01 - 23:30

Analysing the relationship between rainfalls and landslides to define a mosaic of triggering thresholds for regional-scale warning systemsNatural Hazards and Earth System Science, 14, 2637-2648, 2014Author(s): S. Segoni, A. Rosi, G. Rossi, F. Catani, and N. CasagliWe propose an original approach to develop rainfall thresholds to be used in
civil protection warning systems for the occurrence of landslides at
regional scale (i.e. tens of thousands of kilometres), and we apply it to
Tuscany, Italy (23 000 km2).

Purpose-developed software is used to define statistical
intensity–duration rainfall thresholds by means of an automated and
standardized analysis of rainfall data. The automation and standardization
of the analysis brings several advantages that in turn have a positive
impact on the applicability of the thresholds to operational warning
systems. Moreover, the possibility of defining a threshold in very short
times compared to traditional analyses allowed us to subdivide the study area
into several alert zones to be analysed independently, with the aim of setting
up a specific threshold for each of them. As a consequence, a mosaic of
several local rainfall thresholds is set up in place of a single regional
threshold. Even if pertaining to the same region, the local thresholds vary
substantially and can have very different equations. We subsequently
analysed how the physical features of the test area influence the parameters
and the equations of the local thresholds, and found that some threshold
parameters can be put in relation with the prevailing lithology. In
addition, we investigated the possible relations between effectiveness of
the threshold and number of landslides used for the calibration.

A validation procedure and a quantitative comparison with some literature
thresholds showed that the performance of a threshold can be increased if
the areal extent of its test area is reduced, as long as a statistically
significant landslide sample is present. In particular, we demonstrated that
the effectiveness of a warning system can be significantly enhanced if a
mosaic of site-specific thresholds is used instead of a single regional
threshold.

http://www.nat-hazards-earth-syst-sci.net/14/2637/2014/ 2014/10/01 - 23:30

Rockslides on limestone cliffs with subhorizontal bedding in the southwestern calcareous area of ChinaNatural Hazards and Earth System Science, 14, 2627-2635, 2014Author(s): Z. Feng, B. Li, Y. P. Yin, and K. HeCalcareous mountainous areas are highly prone to
geohazards, and rockslides play an important role in cliff retreat. This
study presents three examples of failures of limestone cliffs with
subhorizontal bedding in the southwestern calcareous area of China. Field
observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and
Wangxia Cliff showed that pre-existing vertical joints passing through thick
limestone and the alternation of competent and incompetent layers are the
most significant features for rockslides. A "hard-on-soft" cliff made of
hard rocks superimposed on soft rocks is prone to rock slump, characterized
by shearing through the underlying weak strata along a curved surface and
backward tilting. When a slope contains weak interlayers rather than a soft
basal, a rock collapse could occur from the compression fracture and tensile
split of the rock mass near the interfaces. A rockslide might shear through
a hard rock mass if no discontinuities are exposed in the cliff slope, and
sliding may occur along a moderately inclined rupture plane. The "toe
breakout" mechanism mainly depends on the strength characteristics of the
rock mass.

http://www.nat-hazards-earth-syst-sci.net/14/2627/2014/ 2014/10/01 - 23:30

Bayesian network learning for natural hazard analysesNatural Hazards and Earth System Science, 14, 2605-2626, 2014Author(s): K. Vogel, C. Riggelsen, O. Korup, and F. ScherbaumModern natural hazards research requires dealing with several uncertainties
that arise from limited process knowledge, measurement errors, censored and
incomplete observations, and the intrinsic randomness of the governing
processes. Nevertheless, deterministic analyses are still widely used in
quantitative hazard assessments despite the pitfall of misestimating the
hazard and any ensuing risks.

In this paper we show that Bayesian networks offer a flexible framework for
capturing and expressing a broad range of uncertainties encountered in
natural hazard assessments. Although Bayesian networks are well studied in
theory, their application to real-world data is far from straightforward, and
requires specific tailoring and adaptation of existing algorithms. We offer
suggestions as how to tackle frequently arising problems in this context and
mainly concentrate on the handling of continuous variables, incomplete data
sets, and the interaction of both. By way of three case studies from
earthquake, flood, and landslide research, we demonstrate the method of
data-driven Bayesian network learning, and showcase the flexibility,
applicability, and benefits of this approach.

Our results offer fresh and partly counterintuitive insights into
well-studied multivariate problems of earthquake-induced ground motion
prediction, accurate flood damage quantification, and spatially explicit
landslide prediction at the regional scale. In particular, we highlight how
Bayesian networks help to express information flow and independence
assumptions between candidate predictors. Such knowledge is pivotal in
providing scientists and decision makers with well-informed strategies for
selecting adequate predictor variables for quantitative natural hazard
assessments.

http://www.nat-hazards-earth-syst-sci.net/14/2605/2014/ 2014/10/01 - 23:30

Perception of flood and landslide risk in Italy: a preliminary analysisNatural Hazards and Earth System Science, 14, 2589-2603, 2014Author(s): P. Salvati, C. Bianchi, F. Fiorucci, P. Giostrella, I. Marchesini, and F. GuzzettiInundations and landslides are widespread phenomena in Italy, where they
cause severe damage and pose a threat to the population. Little is known
about the public perception of landslide and flood risk. This is surprising,
as an accurate perception is important for the successful implementation of
many risk reduction or adaptation strategies. In an attempt to address this
gap, we have conducted two national surveys to measure the perception of
landslide and flood risk amongst the population of Italy. The surveys were
conducted in 2012 and 2013, and consisted of approximately 3100
computer-assisted telephone interviews for each survey. The samples of the
interviewees were statistically representative for a national-scale
quantitative assessment. The interviewees were asked questions designed to
obtain information on (i) their perception of natural, environmental, and
technological risks, (ii) direct experience or general knowledge of the
occurrence of landslides and floods in their municipality, (iii) perception
of the possible threat posed by landslides and floods to their safety, (iv)
general knowledge on the number of victims affected by landslides or floods,
and on (v) the factors that the interviewees considered important for
controlling landslide and flood risks in Italy. The surveys revealed that the
population of Italy fears technological risks more than natural risks. Of the
natural risks, earthquakes were considered more dangerous than floods,
landslides, and volcanic eruptions. Examination of the temporal and
geographical distributions of the responses revealed that the occurrence of
recent damaging events influenced risk perception locally, and that the
perception persisted longer for earthquakes and decreased more rapidly for
landslides and floods. We explain the difference by the diverse consequences
of the risks. The interviewees considered inappropriate land management the
main cause of landslide and food risk, followed by illegal construction,
abandonment of the territory, and climate change. Comparison of the risk
perception with actual measures of landslide and flood risk, including the
number of fatal events, the number of fatalities, and the mortality rates,
revealed that in most of the Italian regions, the perception of the threat
did not match the long-term risk posed to the population by landslides and
floods. This outcome points to a need to foster an understanding of the
public towards landslide and flood hazards and risks in Italy.

http://www.nat-hazards-earth-syst-sci.net/14/2589/2014/ 2014/10/01 - 23:30

Revision of the geological context of the Port-au-Prince metropolitan area, Haiti: implications for slope failures and seismic hazard assessmentNatural Hazards and Earth System Science, 14, 2577-2587, 2014Author(s): M. Terrier, A. Bialkowski, A. Nachbaur, C. Prépetit, and Y. F. JosephFollowing the earthquake of 12 January 2010 in the Port-au-Prince area, the
Haitian government, in close cooperation with BRGM, the French geological
Survey, decided to undertake a seismic microzonation study of the
metropolitan area of the capital in order to take more fully into account the
seismic risk in the urbanization and planning of the city under
reconstruction. As the first step of the microzonation project, a geological
study has been carried out. Deposits of Miocene and Pliocene formations in a
marine environment have been identified. These deposits are affected by the
Enriquillo-Plantain Garden N80° E fault system and N110° E faults. Tectonic observations and
morphological analysis indicate Quaternary activity of several faults mapped
in the area of Port-au-Prince. These faults have a N110° trend and
show a reverse-sinistral strike-slip motion. Moreover, on the basis of these
geological results and of new topographical data, a hazard assessment of
ground movements has been made. Along with the map of active faults, the
hazard map of ground movements is an integral component of the seismic
microzonation study.

http://www.nat-hazards-earth-syst-sci.net/14/2577/2014/ 2014/09/26 - 15:09

Earthquake scenario in West Bengal with emphasis on seismic hazard microzonation of the city of Kolkata, IndiaNatural Hazards and Earth System Science, 14, 2549-2575, 2014Author(s): S. K. Nath, M. D. Adhikari, S. K. Maiti, N. Devaraj, N. Srivastava, and L. D. MohapatraSeismic microzonation is a process of estimating
site-specific effects due to an earthquake on urban centers for its disaster
mitigation and management. The state of West Bengal, located in the western
foreland of the Assam–Arakan Orogenic Belt, the Himalayan foothills and Surma
Valley, has been struck by several devastating earthquakes in the past,
indicating the need for a seismotectonic review of the province, especially
in light of probable seismic threat to its capital city of Kolkata, which
is a major industrial and commercial hub in the eastern and northeastern
region of India. A synoptic probabilistic seismic hazard model of Kolkata is
initially generated at engineering bedrock (Vs30 ~ 760 m s−1)
considering 33 polygonal seismogenic sources at two hypocentral
depth ranges, 0–25 and 25–70 km; 158 tectonic sources; appropriate
seismicity modeling; 14 ground motion prediction equations for three
seismotectonic provinces, viz. the east-central Himalaya, the Bengal Basin and
Northeast India selected through suitability testing; and appropriate
weighting in a logic tree framework. Site classification of Kolkata
performed following in-depth geophysical and geotechnical investigations
places the city in D1, D2, D3 and E classes. Probabilistic seismic hazard
assessment at a surface-consistent level – i.e., the local seismic hazard related
to site amplification performed by propagating the bedrock ground motion
with 10% probability of exceedance in 50 years through a 1-D sediment column
using an equivalent linear analysis – predicts a peak ground acceleration
(PGA) range from 0.176 to 0.253 g in the city. A deterministic liquefaction
scenario in terms of spatial distribution of liquefaction potential index
corresponding to surface PGA distribution places 50% of the city in the
possible liquefiable zone. A multicriteria seismic hazard microzonation
framework is proposed for judicious integration of multiple themes, namely
PGA at the surface, liquefaction potential index, NEHRP
soil site class, sediment class, geomorphology and ground water table in a
fuzzy protocol in the geographical information system by adopting an
analytical hierarchal process. The resulting high-resolution surface
consistent hazard, liquefaction and microzonation maps are expected to play
vital roles in earthquake-related disaster mitigation and management
of the city of Kolkata.

http://www.nat-hazards-earth-syst-sci.net/14/2549/2014/ 2014/09/25 - 13:25

Decision-tree analysis of factors influencing rainfall-related building structure and content damageNatural Hazards and Earth System Science, 14, 2531-2547, 2014Author(s): M. H. Spekkers, M. Kok, F. H. L. R. Clemens, and J. A. E. ten VeldhuisFlood-damage prediction models are essential building blocks in
flood risk assessments. So far, little research has been dedicated to
damage from small-scale urban floods caused by heavy rainfall, while
there is a need for reliable damage models for this flood type among
insurers and water authorities.

The aim of this paper is to investigate a wide range of
damage-influencing factors and their relationships with
rainfall-related damage, using decision-tree analysis. For this,
district-aggregated claim data from private property insurance
companies in the Netherlands were analysed, for the period 1998–2011.
The databases include claims of water-related damage (for example, damages related to rainwater intrusion through roofs
and pluvial flood water entering buildings at ground floor). Response
variables being modelled are average claim size and claim frequency,
per district, per day. The set of predictors include rainfall-related
variables derived from weather radar images, topographic variables
from a digital terrain model, building-related variables and
socioeconomic indicators of households.

Analyses were made separately for property and content damage claim
data. Results of decision-tree analysis show that claim frequency is
most strongly associated with maximum hourly rainfall intensity,
followed by real estate value, ground floor area, household income,
season (property data only), buildings age (property data only),
a fraction of homeowners (content data only), a and fraction of low-rise
buildings (content data only). It was not possible to develop statistically
acceptable trees for average claim size. It is recommended to investigate
explanations for the failure to derive models. These require the inclusion
of other explanatory factors that were not used in the present study, an
investigation of the variability in average claim size at different spatial
scales, and the collection of more detailed insurance data that allows one to
distinguish between the effects of various damage mechanisms to claim size.
Cross-validation results show that decision trees were able
to predict 22–26% of variance in claim frequency, which is
considerably better compared to results from global multiple
regression models (11–18% of variance explained). Still,
a large part of the variance in claim frequency is left unexplained,
which is likely to be caused by variations in data at subdistrict
scale and missing explanatory variables.

http://www.nat-hazards-earth-syst-sci.net/14/2531/2014/ 2014/09/25 - 13:25

Corrigendum to "Analysis of the French insurance market exposure to floods: a stochastic model combining river overflow and surface runoff" published in Nat. Hazards Earth Syst. Sci., 14, 2469–2485, 2014Natural Hazards and Earth System Science, 14, 2529-2529, 2014Author(s): D. Moncoulon, D. Labat, J. Ardon, E. Leblois, T. Onfroy, C. Poulard, S. Aji, A. Rémy, and A. QuantinNo abstrace available.

http://www.nat-hazards-earth-syst-sci.net/14/2529/2014/ 2014/09/25 - 13:25

A preliminary investigation of rogue waves off the Jiangsu coast, ChinaNatural Hazards and Earth System Science, 14, 2521-2527, 2014Author(s): Y. Wang, A.-F. Tao, J.-H. Zheng, D.-J. Doong, J. Fan, and J. PengDue to the potential disasters induced by rogue waves, research in this field
has increased rapidly in the last 2 decades. However, there are still a lot
of open questions left, including some classic ones, such as whether the
rogues waves are just rare events or not. One of the key reasons is that not
enough of the observed rogue waves have been investigated. China has a wide
sea area, but none of the research has addressed the observed rogue waves. In
the present study, 1 year of observed wave data from Jiangsu coastal area, China, are
analyzed. It is found that rogue waves are present, although the
wave heights are not very large; furthermore, the probability of their
occurrence is similar to the Rayleigh distribution prediction, due to the
local silty coastal topography. The characteristics of rouge waves are
investigated and the results indicate that a new type of rogue wave may
exist.

http://www.nat-hazards-earth-syst-sci.net/14/2521/2014/ 2014/09/25 - 13:25

Estimating velocity from noisy GPS data for investigating the temporal variability of slope movementsNatural Hazards and Earth System Science, 14, 2503-2520, 2014Author(s): V. Wirz, J. Beutel, S. Gruber, S. Gubler, and R. S. PurvesDetecting and monitoring of moving and potentially hazardous slopes requires
reliable estimations of velocities. Separating any movement signal from
measurement noise is crucial for understanding the temporal variability of
slope movements and detecting changes in the movement regime, which may be
important indicators of the process. Thus, methods capable of estimating velocity
and its changes reliably are required. In this paper we develop and test a
method for deriving velocities based on noisy GPS (Global Positioning System) data, suitable for various
movement patterns and variable signal-to-noise-ratios (SNR). We tested this
method on synthetic data, designed to mimic the characteristics of diverse
processes, but where we have full knowledge of the underlying velocity
patterns, before applying it to explore data collected.

http://www.nat-hazards-earth-syst-sci.net/14/2503/2014/ 2014/09/23 - 08:14

The XWS open access catalogue of extreme European windstorms from 1979 to 2012Natural Hazards and Earth System Science, 14, 2487-2501, 2014Author(s): J. F. Roberts, A. J. Champion, L. C. Dawkins, K. I. Hodges, L. C. Shaffrey, D. B. Stephenson, M. A. Stringer, H. E. Thornton, and B. D. YoungmanThe XWS (eXtreme WindStorms) catalogue consists of storm tracks and model-generated maximum
3 s wind-gust footprints for 50 of the most extreme winter windstorms to hit Europe in the period
1979–2012. The catalogue is intended to be a valuable resource for both academia and industries
such as (re)insurance, for example allowing users to characterise extreme European storms, and
validate climate and catastrophe models. Several storm severity indices were investigated to find
which could best represent a list of known high-loss (severe) storms. The best-performing index
was Sft, which is a combination of storm area calculated from the storm footprint and
maximum 925 hPa wind speed from the storm track. All the listed severe storms are
included in the catalogue, and the remaining ones were selected using Sft.
A comparison of the model footprint to station observations revealed that storms were generally
well represented, although for some storms the highest gusts were underestimated.
Possible reasons for this underestimation include the model failing to simulate strong enough
pressure gradients and not representing convective gusts.

A new recalibration method was developed to estimate the true distribution of gusts at
each grid point and correct for this underestimation. The recalibration model allows for storm-to-storm
variation which is essential given that different storms have different degrees of model bias. The
catalogue is available at http://www.europeanwindstorms.org .

http://www.nat-hazards-earth-syst-sci.net/14/2487/2014/ 2014/09/23 - 08:14

Analysis of the French insurance market exposure to floods: a stochastic model combining river overflow and surface runoffNatural Hazards and Earth System Science, 14, 2469-2485, 2014Author(s): D. Moncoulon, D. Labat, J. Ardon, E. Leblois, T. Onfroy, C. Poulard, S. Aji, A. Rémy, and A. QuantinThe analysis of flood exposure at a national scale for the French insurance
market must combine the generation of a probabilistic event set of all
possible (but which have not yet occurred) flood situations with hazard and
damage modeling. In this study, hazard and damage models are calibrated on a
1995–2010 historical event set, both for hazard results (river flow, flooded
areas) and loss estimations. Thus, uncertainties in the deterministic
estimation of a single event loss are known before simulating a probabilistic
event set. To take into account at least 90 % of the insured flood losses,
the probabilistic event set must combine the river overflow (small and large
catchments) with the surface runoff, due to heavy rainfall, on the slopes of
the watershed. Indeed, internal studies of the CCR (Caisse Centrale de
Reassurance) claim database have shown that approximately 45 % of the
insured flood losses are located inside the floodplains and 45 % outside.
Another 10 % is due to sea surge floods and groundwater rise. In this
approach, two independent probabilistic methods are combined to create a
single flood loss distribution: a generation of fictive river flows based on
the historical records of the river gauge network and a generation of fictive
rain fields on small catchments, calibrated on the 1958–2010
Météo-France rain database SAFRAN. All the events in the
probabilistic event sets are simulated with the deterministic model. This
hazard and damage distribution is used to simulate the flood losses at the
national scale for an insurance company (Macif) and to generate flood areas
associated with hazard return periods. The flood maps concern river overflow
and surface water runoff. Validation of these maps is conducted by comparison
with the address located claim data on a small catchment (downstream Argens).

http://www.nat-hazards-earth-syst-sci.net/14/2469/2014/ 2014/09/20 - 18:28

Shallow landslide prediction and analysis with risk assessment using a spatial model in a coastal region in the state of São Paulo, BrazilNatural Hazards and Earth System Science, 14, 2449-2468, 2014Author(s): P. I. M. Camarinha, V. Canavesi, and R. C. S. AlvaláThis study presents a methodology for susceptibility mapping of shallow
landslides just from data and software from the public domain. The study was
conducted in a mountainous region located on the southeastern Brazilian
coast, in the state of São Paulo. The proposal is that the methodology
can be replicated in a practical and reliable way in several other
municipalities that do not have such mappings and that often suffer from
landslide-related disasters. The susceptibility mapping was generated based
on the following maps: geological, soils, slope, horizontal and vertical
curvatures, and land use. The thematic classes of these maps were weighted
according to technical and scientific criteria related to the triggering of
landslides, and were crossed by the fuzzy gamma technique. The mapping was
compared with the risk sector survey made by the Brazilian Geological Survey
(CPRM), which is the official database used by municipalities and civil
defense in risk management. The results showed positive correlations, so that
the critical risk sectors had higher proportions for the more susceptible
classes. To compare the approach with other studies using landslide-scar
maps, correlated indices were evaluated, which also showed satisfactory
results, thus indicating that the methodology presented is appropriate for
risk assessment in urban areas.

http://www.nat-hazards-earth-syst-sci.net/14/2449/2014/ 2014/09/20 - 18:28

Risk identification of agricultural drought for sustainable AgroecosystemsNatural Hazards and Earth System Science, 14, 2435-2448, 2014Author(s): N. R. Dalezios, A. Blanta, N. V. Spyropoulos, and A. M. TarquisDrought is considered as one of the major natural hazards with a significant
impact on agriculture, environment, society and economy. Droughts affect
sustainability of agriculture and may result in environmental degradation of
a region, which is one of the factors contributing to the vulnerability of
agriculture. This paper addresses agrometeorological or agricultural drought
within the risk management framework. Risk management consists of risk
assessment, as well as a feedback on the adopted risk reduction measures.
And risk assessment comprises three distinct steps, namely risk
identification, risk estimation and risk evaluation. This paper deals with
risk identification of agricultural drought, which involves drought
quantification and monitoring, as well as statistical
inference. For the quantitative assessment of agricultural drought,
as well as the computation of spatiotemporal features, one of the most
reliable and widely used indices is applied, namely the vegetation health
index (VHI). The computation of VHI is based on satellite data of
temperature and the normalized difference vegetation index (NDVI). The
spatiotemporal features of drought, which are extracted from VHI, are areal
extent, onset and end time, duration and severity. In this paper, a 20-year
(1981–2001) time series of the National Oceanic and Atmospheric Administration/advanced very high resolution radiometer (NOAA/AVHRR) satellite data is used, where monthly
images of VHI are extracted. Application is implemented in Thessaly, which
is the major agricultural drought-prone region of Greece, characterized by
vulnerable agriculture. The results show that agricultural drought appears
every year during the warm season in the region. The severity of drought is
increasing from mild to extreme throughout the warm season, with peaks
appearing in the summer. Similarly, the areal extent of drought is also
increasing during the warm season, whereas the number of extreme drought
pixels is much less than those of mild to moderate drought throughout the
warm season. Finally, the areas with diachronic drought persistence can be
located. Drought early warning is developed using empirical functional
relationships of severity and areal extent. In particular, two second-order
polynomials are fitted, one for low and the other for high severity drought
classes, respectively. The two fitted curves offer a forecasting tool on a
monthly basis from May to October. The results of this drought risk
identification effort are considered quite satisfactory offering a
prognostic potential. The adopted remote-sensing data and methods have
proven very effective in delineating spatial variability and features in
drought quantification and monitoring.

http://www.nat-hazards-earth-syst-sci.net/14/2435/2014/ 2014/09/12 - 22:15

Rainstorms able to induce flash floods in a Mediterranean-climate region (Calabria, southern Italy)Natural Hazards and Earth System Science, 14, 2423-2434, 2014Author(s): O. G. Terranova and S. L. GarianoHeavy rainstorms often induce flash flooding, one of the natural disasters
most responsible for damage to man-made infrastructures and loss of lives,
also adversely affecting the opportunities for socio-economic development of
Mediterranean countries. The frequently dramatic damage of flash floods are
often detected, with sufficient accuracy, by post-event surveys, but rainfall
causing them are still only roughly characterized. With the aim of improving
the understanding of the temporal structure and spatial distribution of
heavy rainstorms in the Mediterranean context, a statistical analysis was
carried out in Calabria (southern Italy) concerning rainstorms that mainly
induced flash floods, but also shallow landslides and debris flows. Thus, a
method is proposed – based on the overcoming of heuristically predetermined
threshold values of cumulated rainfall, maximum intensity, and kinetic
energy of the rainfall event – to select and characterize the rainstorms
able to induce flash floods in the Mediterranean-climate countries.
Therefore, the obtained (heavy) rainstorms were automatically classified and
studied according to their structure in time, localization, and extension.
Rainfall-runoff watershed models can consequently benefit from the enhanced
identification of design storms, with a realistic time structure integrated
with the results of the spatial analysis. A survey of flash flood events
recorded in the last decades provides a preliminary validation of the method
proposed to identify the heavy rainstorms and synthetically describe their
characteristics. The notable size of the employed sample, including data
with a very detailed resolution in time that relate to several rain gauges
well-distributed throughout the region, gives robustness to the obtained
results.

http://www.nat-hazards-earth-syst-sci.net/14/2423/2014/ 2014/09/11 - 17:16

Analysis of synoptic conditions for tornadic days over western GreeceNatural Hazards and Earth System Science, 14, 2409-2421, 2014Author(s): P. T. Nastos and I. T. MatsangourasTornadoes have been reported in Greece during the last few decades and recent
studies have given evidence that western Greece is an area vulnerable to
tornadoes, waterspouts and funnel clouds In this study, the composite means
and anomalies of synoptic conditions for tornadic events (tornadoes,
waterspouts and funnel clouds) over western Greece are analyzed and
discussed.

The daily composite means of synoptic conditions were based on the National
Centers for Environmental Prediction–National Center for Atmospheric
Research (NCEP–NCAR) reanalysis data sets, for the period 12 August 1953 to
31 December 2012. The daily composite anomalies were calculated with respect
to 30 years of climatological study (1981–2010) of the synoptic conditions.
The analysis was carried out in terms of seasonal and monthly variability of
composite means and anomalies of synoptic conditions for specific isobaric
levels of 500, 700, 850, 925 hPa and the sea level pressure (SLP). In
addition, an analysis and discussion about the dynamic lifted index from
NCEP–NCAR reanalysis data sets is presented.

The daily composite mean analysis of 500 hPa revealed a trough line across
the northern Adriatic Sea and central Italy, associated with a SW upper-air
stream over western Greece. The maximum composite anomalies were depicted at
the isobaric level of 500 hPa during autumn, spring and summer,
against winter when the anomaly appeared at 925 hPa isobaric level. In
addition, 48% of tornado events during the autumn season occurred in
pre-frontal weather conditions (cold fronts) and 27% developed after the
passage of the cold front. Furthermore, the main difference in synoptic
patterns between tornado and waterspout days along western Greece during the
autumn season is the maximum daily composite anomaly over the Gulf of
Taranto.

http://www.nat-hazards-earth-syst-sci.net/14/2409/2014/ 2014/09/11 - 17:16

Automated reconstruction of rainfall events responsible for shallow landslidesNatural Hazards and Earth System Science, 14, 2399-2408, 2014Author(s): G. Vessia, M. Parise, M. T. Brunetti, S. Peruccacci, M. Rossi, C. Vennari, and F. GuzzettiOver the last 40 years, many contributions have identified empirical rainfall
thresholds (e.g. rainfall intensity (I) vs. rainfall duration (D),
cumulated rainfall vs. rainfall duration (ED), cumulated rainfall vs.
rainfall intensity (EI)) for the possible initiation of shallow landslides,
based on local and global inventories. Although different methods to trace
the threshold curves have been proposed and discussed in literature, a
systematic study to develop an automated procedure to select the rainfall
event responsible for the landslide occurrence has only rarely been
addressed. Objective criteria for estimating the rainfall responsible for the
landslide occurrence play a prominent role on the threshold values. In this
paper, two criteria for the identification of the effective rainfall events
are presented. The first criterion is based on the analysis of the time
series of rainfall mean intensity values over 1 month preceding the landslide
occurrence. The second criterion is based on the analysis of the trend in the
time function of the cumulated mean intensity series calculated from the
rainfall records measured through rain gauges. The two criteria have been
implemented in an automated procedure that is written in the R language. A
sample of 100 shallow landslides collected in Italy from 2002 to 2012 was
used to calibrate the procedure. The cumulated event rainfall (E) and
duration (D) of rainfall events that triggered the documented landslides
are calculated through the new procedure and are fitted with power law in the
D, E diagram. The results are discussed by comparing the D, E pairs
calculated by the automated procedure and the ones by the expert method.

http://www.nat-hazards-earth-syst-sci.net/14/2399/2014/ 2014/09/11 - 17:16

Bayesian trend analysis of extreme wind using observed and hindcast series off the Catalan coast, NW Mediterranean SeaNatural Hazards and Earth System Science, 14, 2387-2397, 2014Author(s): M. I. Ortego, J. J. Egozcue, and R. Tolosana-DelgadoIt has been suggested that climate change might modify the occurrence rate
and magnitude of large ocean-wave and wind storms. The hypothesised reason is
the increase of available energy in the atmosphere–ocean system. Forecasting
models are commonly used to assess these effects, given that good-quality
data series are often too short. However, forecasting systems are often tuned
to reproduce the average behaviour, and there are concerns on their relevance
for extremal regimes. We present a methodology of simultaneous analysis of
observed and hindcast data with the aim of extracting potential time drifts
as well as systematic regime discrepancies between the two data sources. The
method is based on the peak-over-threshold (POT) approach and the generalized
Pareto distribution (GPD) within a Bayesian estimation framework. In this
context, storm events are considered points in time, and modelled as
a Poisson process. Storm magnitude over a reference threshold is modelled
with a GPD, a flexible model that captures the tail behaviour of the
magnitude distribution.

All model parameters, i.e. shape and location of the magnitude GPD and the
Poisson occurrence rate, are affected by a trend in time. Moreover, a
systematic difference between parameters of hindcast and observed series is
considered. Finally, the posterior joint distribution of all these trend
parameters is studied using a conventional Gibbs sampler. This method is
applied to compare hindcast and observed series of average wind speed at
a deep buoy location off the Catalan coast (NE Spain, western Mediterranean;
buoy data from 2001; REMO wind hindcasting from 1958 on). Appropriate scale
and domain of attraction are discussed, and the reliability of trends in time
is addressed.

http://www.nat-hazards-earth-syst-sci.net/14/2387/2014/ 2014/09/11 - 17:16

Agricultural losses related to frost events: use of the 850 hPa level temperature as an explanatory variable of the damage costNatural Hazards and Earth System Science, 14, 2375-2386, 2014Author(s): K. Papagiannaki, K. Lagouvardos, V. Kotroni, and G. PapagiannakisThe objective of this study is the analysis of damaging frost events in
agriculture, by examining the relationship between the daily minimum
temperature in the lower atmosphere (at an isobaric level of 850 hPa) and
crop production losses. Furthermore, the study suggests a methodological
approach for estimating agriculture risk due to frost events, with the aim of
estimating the short-term probability and magnitude of frost-related
financial losses for different levels of 850 hPa temperature. Compared with
near-surface temperature forecasts, temperature forecasts at the level of
850 hPa are less influenced by varying weather conditions or by local
topographical features; thus, they constitute a more consistent indicator of
the forthcoming weather conditions.

The analysis of the daily monetary compensations for insured crop losses caused by weather events in Greece shows that, during the period 1999–2011, frost caused more damage to crop production than any other meteorological phenomenon. Two regions of different
geographical latitudes are examined further, to account for the differences
in the temperature ranges developed within their ecological environment.
Using a series of linear and logistic regressions, we found that minimum
temperature (at an 850 hPa level), grouped into three categories according
to its magnitude, and seasonality, are significant variables when trying to
explain crop damage costs, as well as to predict and quantify the likelihood
and magnitude of damaging frost events.

http://www.nat-hazards-earth-syst-sci.net/14/2375/2014/ 2014/09/09 - 01:15

Corrigendum to "Modelling wildland fire propagation by tracking random fronts" published in Nat. Hazards Earth Syst. Sci., 14, 2249–2263, 2014Natural Hazards and Earth System Science, 14, 2373-2373, 2014Author(s): G. Pagnini and A. MentrelliNo abstract available.

http://www.nat-hazards-earth-syst-sci.net/14/2373/2014/ 2014/09/09 - 01:15

Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere–fire numerical modelNatural Hazards and Earth System Science, 14, 2359-2371, 2014Author(s): C. C. Simpson, J. J. Sharples, and J. P. EvansVorticity-driven lateral fire spread (VLS) is a form of
dynamic fire behaviour, during which a wildland fire spreads rapidly across a
steep leeward slope in a direction approximately transverse to the background
winds. VLS is often accompanied by a downwind extension of the active flaming
region and intense pyro-convection. In this study, the WRF-Fire
(WRF stands for Weather Research and Forecasting) coupled
atmosphere–fire model is used to examine the sensitivity of resolving VLS to
both the horizontal and vertical grid spacing, and the fire-to-atmosphere
coupling from within the model framework. The atmospheric horizontal and
vertical grid spacing are varied between 25 and 90 m, and the
fire-to-atmosphere coupling is either enabled or disabled. At high spatial
resolutions, the inclusion of fire-to-atmosphere coupling increases the
upslope and lateral rate of spread by factors of up to 2.7 and 9.5,
respectively. This increase in the upslope and lateral rate of spread
diminishes at coarser spatial resolutions, and VLS is not modelled for a
horizontal and vertical grid spacing of 90 m. The lateral fire spread is
driven by fire whirls formed due to an interaction between the background
winds and the vertical circulation generated at the flank of the fire front
as part of the pyro-convective updraft. The laterally advancing fire fronts
become the dominant contributors to the extreme pyro-convection. The results
presented in this study demonstrate that both high spatial resolution and
two-way atmosphere–fire coupling are required to model VLS with WRF-Fire.

http://www.nat-hazards-earth-syst-sci.net/14/2359/2014/ 2014/09/06 - 14:29

Reducing volcanic risk on Fogo Volcano, Cape Verde, through a participatory approach: which outcome?Natural Hazards and Earth System Science, 14, 2347-2358, 2014Author(s): P. Texier-Teixeira, F. Chouraqui, A. Perrillat-Collomb, F. Lavigne, J. R. Cadag, and D. GrancherThis research paper
presents the outcomes of Work Package 5 (socio-economical vulnerability
assessment and community-based disaster risk reduction) of the MIAVITA
(MItigate and Assess risk from Volcanic Impact on Terrain and human
Activities) research programme conducted on Fogo Volcano, Cape Verde. The
study lasted for almost 3 years (May 2010 to January 2012), of which most of
the time was spent in the village of Chã das Caldeiras, situated within
the 9 km wide caldera of the volcano inside Fogo Natural Park. The
objectives of the programme included assessment of the vulnerability of the
community at risk in terms of livelihoods, access to resources, and power
relations between the local people and the different public and private
institutions. These are important factors that need to be investigated in
order to understand the root causes of vulnerability of the local people.
This case study shows that the voluntary exposure of people to volcanic
threats is linked to daily access to sources of livelihood, especially
agriculture and tourism. This is despite the perception of people of the risk
to their lives and properties. In order to counter the factors of
vulnerability, the study also aimed to identify and enhance local capacities.
To achieve such an objective, a participatory three-dimensional mapping
(P3DM) activity was conducted to facilitate the dialogue between the local
people and the different stakeholders as well as to prepare plans and
measures to reduce volcanic risk. The P3DM was a half success considering
that it has not yet led to an operational plan which takes into account the
local capacities. The main reasons included (1) the non-participatory aspect
of the project at the beginning which should have identified priorities for
people and let them lead the project to ensure the sustainability of (2) deep
conflicts within the community which complicated the focus group discussions
around the 3-D map, and the difficulties in involving more marginalised
people like women and the youth, and (3) the fact that volcanic risk is not a
priority for the people, who are more concerned with daily difficulties due
to unsustainable livelihoods, a lack of access to water, land tenure, and the
restrictions by the Fogo Natural Park administration and the municipal
officials.

Still, the study was successful in creating a space for dialogue between the
local people and the outside stakeholders such as the Natural Park
Administration, the Civil Protection, and the Municipality of Santa Catarina,
who have all participated actively during the course of the project.

http://www.nat-hazards-earth-syst-sci.net/14/2347/2014/ 2014/09/06 - 14:29

PM1 measurements at a site close to an oil/gas pre-treatment plant (Agri Valley – southern Italy): a preliminary studyNatural Hazards and Earth System Science, 14, 2337-2346, 2014Author(s): S. Trippetta, R. Caggiano, and S. SabiaA PM1 (i.e. particulate matter with an aerodynamic
diameter less than 1.0 μm) short-term monitoring campaign was
carried out in the Agri Valley (southern Italy) in September 2012. This area
is of international concern, since it houses one of the largest European
on-shore reservoirs and the largest oil/gas pre-treatment plant (i.e. the
Centro Olio Val d'Agri – COVA) within an anthropised context. PM1
measurements were performed in Viggiano, the nearest town to the COVA plant
and one of the most populated towns of the Agri Valley. During the study
period, the PM1 daily concentrations ranged from 1.2 to
8.4 μg m−3, with a mean value of 4.6 μg m−3.
Regarding the PM1 chemical composition, it can be observed that S and
typical crustal elements were the most abundant constituents of the PM1
collected. By applying principal component analysis (PCA), it was pointed out
that crustal soil, biomass and wood burning, secondary atmospheric reactions
involving COVA plant emissions and local soil particles, and traffic were the
main sources contributing to the PM1 measured in the area under study.
Moreover, a possible contribution of the long-range transport of African dust
was observed.

http://www.nat-hazards-earth-syst-sci.net/14/2337/2014/ 2014/09/03 - 20:13

Stochastic daily precipitation model with a heavy-tailed componentNatural Hazards and Earth System Science, 14, 2321-2335, 2014Author(s): N. M. Neykov, P. N. Neytchev, and W. ZucchiniStochastic daily precipitation
models are commonly used to generate scenarios of climate variability or
change on a daily timescale. The standard models consist of two components
describing the occurrence and intensity series, respectively. Binary logistic
regression is used to fit the occurrence data, and the intensity series is
modeled using a continuous-valued right-skewed distribution, such as gamma,
Weibull or lognormal. The precipitation series is then modeled using the
joint density, and standard software for generalized linear models can be
used to perform the computations. A drawback of these precipitation models is
that they do not produce a sufficiently heavy upper tail for the distribution
of daily precipitation amounts; they tend to underestimate the frequency of
large storms. In this study, we adapted the approach of
Furrer and Katz (2008) based on hybrid distributions in order to correct for
this shortcoming. In particular, we applied hybrid gamma–generalized Pareto
(GP) and hybrid Weibull–GP distributions to develop a stochastic
precipitation model for daily rainfall at Ihtiman in western Bulgaria. We
report the results of simulations designed to compare the models based on the
hybrid distributions and those based on the standard distributions. Some
potential difficulties are outlined.

http://www.nat-hazards-earth-syst-sci.net/14/2321/2014/ 2014/09/03 - 20:13

Development of models for maximum and time variation of storm surges at the Tanshui estuaryNatural Hazards and Earth System Science, 14, 2313-2320, 2014Author(s): C.-P. Tsai and C.-Y. YouIn this study, artificial neural networks, including both
multilayer perception and the radial basis function neural networks, are
applied for modeling and forecasting the maximum and time variation of
storm surges at the Tanshui estuary in Taiwan. The physical parameters,
including both the local atmospheric pressure and the wind field factors,
for finding the maximum storm surges, are first investigated based on the
training of neural networks. Then neural network models for forecasting the
time series of storm surges are accordingly developed using the major
meteorological parameters with time variations. The time series of storm
surges for six typhoons were used for training and testing the models, and
data for three typhoons were used for model forecasting. The results show
that both neural network models perform very well for the forecasting of the
time variation of storm surges.

http://www.nat-hazards-earth-syst-sci.net/14/2313/2014/ 2014/09/03 - 20:13

A multi-scale risk assessment for tephra fallout and airborne concentration from multiple Icelandic volcanoes – Part 2: Vulnerability and impactNatural Hazards and Earth System Science, 14, 2289-2312, 2014Author(s): C. Scaini, S. Biass, A. Galderisi, C. Bonadonna, A. Folch, K. Smith, and A. HöskuldssonWe perform a multi-scale impact assessment of tephra fallout and dispersal
from explosive volcanic activity in Iceland. A companion paper (Biass et al.,
2014; "A multi-scale risk assessment of tephra fallout and airborne
concentration from multiple Icelandic volcanoes – Part I: hazard
assessment") introduces a multi-scale probabilistic assessment of tephra
hazard based on selected eruptive scenarios at four Icelandic volcanoes (Hekla,
Askja, Eyjafjallajökull and Katla) and presents probabilistic hazard maps
for tephra accumulation in Iceland and tephra dispersal across Europe. Here,
we present the associated vulnerability and impact assessment that describes
the importance of single features at national and European levels and
considers several vulnerability indicators for tephra dispersal and
deposition. At the national scale, we focus on physical, systemic and economic
vulnerability of Iceland to tephra fallout, whereas at the European scale we
focus on the systemic vulnerability of the air traffic system to tephra
dispersal. This is the first vulnerability and impact assessment analysis of
this type and, although it does not include all the aspects of physical and
systemic vulnerability, it allows for identifying areas on which further specific
analysis should be performed. Results include vulnerability maps for Iceland
and European airspace and allow for the qualitative identification of the
impacts at both scales in the case of an eruption occurring. Maps produced at
the national scale show that tephra accumulation associated with all eruptive
scenarios considered can disrupt the main electricity network, in particular in
relation to an eruption of Askja. Results also show that several power plants
would be affected if an eruption occurred at Hekla, Askja or Katla, causing a substantial systemic impact due to their
importance for the Icelandic economy. Moreover, the Askja and Katla eruptive
scenarios considered could have substantial impacts on agricultural
activities (crops and pastures). At the European scale, eruptive scenarios at
Askja and Katla are likely to affect European airspace, having
substantial impacts, in particular, in the Keflavík and London flight
information regions (FIRs), but also at FIRs above France, Germany and
Scandinavia. Impacts would be particularly intense in the case of long-lasting
activity at Katla. The occurrence of eruptive scenarios at Hekla is likely to produce high impacts at Keflavík FIR and London FIRs,
and, in the case of higher magnitude, can also impact France's FIRs. Results could
support land use and emergency planning at the national level and risk management
strategies of the European air traffic system. Although we focus on Iceland,
the proposed methodology could be applied to other active volcanic areas,
enhancing the long-term tephra risk management. Moreover, the outcomes of
this work pose the basis for quantitative analyses of expected impacts and
their integration in a multi-risk framework.

http://www.nat-hazards-earth-syst-sci.net/14/2289/2014/ 2014/08/30 - 21:21

A multi-scale risk assessment for tephra fallout and airborne concentration from multiple Icelandic volcanoes – Part 1: Hazard assessmentNatural Hazards and Earth System Science, 14, 2265-2287, 2014Author(s): S. Biass, C. Scaini, C. Bonadonna, A. Folch, K. Smith, and A. HöskuldssonIn order to assist the elaboration of proactive measures for the management
of future volcanic eruptions in Iceland, we developed a new scenario-based approach to
assess the hazard associated with tephra dispersal and sedimentation at
various scales and for multiple sources. The target volcanoes are Hekla,
Katla, Eyjafjallajökull and Askja, selected either for their high
probabilities of eruption and/or their high potential impact. By coupling
tephrostratigraphic studies, probabilistic techniques and modelling, we
developed comprehensive eruption scenarios for both short- and long-lasting
eruptions and compiled hazard maps for tephra ground deposition at a national
scale and air concentration at a European scale using the TEPHRA2 and FALL3D
models, respectively. New algorithms for the identification of realistic sets
of eruptive source parameters are investigated, which assist the generation
of probability density functions of eruption source parameters for the
selected scenarios. Aggregation processes were accounted for using various
empirical models. Outcomes, i.e. probabilities conditioned to the occurrence of an eruption,
help the assessment and comparison of hazard levels at
different scales. For example, at a national scale Askja has a 5–10%
probability of blanketing the easternmost half of the country with a tephra
accumulation of at least 1 kg m−2. At a continental scale, Katla
has a 5–10% probability of producing ash clouds with concentrations of
2 mg m−3 over the UK, Scandinavia and northern Europe with a mean
arrival time of 48–72 h and a mean persistence time of 6–18 h. In a
companion paper, Scaini et al. (2014) present a vulnerability assessment for
Iceland to ground deposition of tephra and for the European air traffic to
airborne ash which, combined with the outcomes of the present paper,
constitute one of the first comprehensive multi-scale risk assessment associated with
tephra dispersal and sedimentation.

http://www.nat-hazards-earth-syst-sci.net/14/2265/2014/ 2014/08/30 - 21:21

Modelling wildland fire propagation by tracking random frontsNatural Hazards and Earth System Science, 14, 2249-2263, 2014Author(s): G. Pagnini and A. MentrelliWildland fire propagation is studied in the literature by two alternative
approaches, namely the reaction–diffusion equation and the level-set method.
These two approaches are considered alternatives to each other because the
solution of the reaction–diffusion equation is generally a continuous smooth
function that has an exponential decay, and it is not zero in an infinite
domain, while the level-set method, which is a front tracking technique,
generates a sharp function that is not zero inside a compact domain. However,
these two approaches can indeed be considered complementary and reconciled.
Turbulent hot-air transport and fire spotting are phenomena with a random nature and
they are extremely important in wildland fire propagation.
Consequently, the fire front gets a random character, too; hence, a tracking
method for random fronts is needed. In particular, the level-set contour is
randomised here according to the
probability density function of the interface particle displacement.
Actually, when the level-set method is developed for tracking a front
interface with a random motion, the resulting averaged process emerges to be
governed by an evolution equation of the reaction–diffusion type. In this
reconciled approach, the rate of spread of the fire keeps the same key and
characterising role that is typical of the level-set approach. The resulting
model emerges to be suitable for simulating effects due to turbulent
convection, such as fire flank and backing fire, the faster fire spread being
because of the actions by hot-air pre-heating and by ember landing, and also
due to the fire overcoming a fire-break zone, which is a case not resolved by models based on the
level-set method. Moreover, from the proposed formulation, a correction follows
for the formula of the rate of spread which is due to the mean jump length of
firebrands in the downwind direction
for the leeward sector of the fireline contour. The presented
study constitutes a proof of concept, and it needs to be subjected to a future validation.

http://www.nat-hazards-earth-syst-sci.net/14/2249/2014/ 2014/08/29 - 02:07

Computational snow avalanche simulation in forested terrainNatural Hazards and Earth System Science, 14, 2233-2248, 2014Author(s): M. Teich, J.-T. Fischer, T. Feistl, P. Bebi, M. Christen, and A. Grêt-RegameyTwo-dimensional avalanche simulation software operating in three-dimensional
terrain is widely used for hazard zoning and engineering to predict runout
distances and impact pressures of snow avalanche events. Mountain forests are
an effective biological protection measure against avalanches; however, the
protective capacity of forests to decelerate or even to stop avalanches that
start within forested areas or directly above the treeline is seldom
considered in this context. In particular, runout distances of small- to
medium-scale avalanches are strongly influenced by the structural conditions
of forests in the avalanche path. We present an evaluation and
operationalization of a novel detrainment function implemented in the
avalanche simulation software RAMMS for avalanche simulation in forested
terrain. The new approach accounts for the effect of forests in the avalanche
path by detraining mass, which leads to a deceleration and runout shortening
of avalanches. The relationship is parameterized by the detrainment
coefficient K [kg m−1 s−2] accounting for differing forest
characteristics. We varied K when simulating 40 well-documented small- to
medium-scale avalanches, which were released in and ran through forests of
the Swiss Alps. Analyzing and comparing observed and simulated runout
distances statistically revealed values for K suitable to simulate the
combined influence of four forest characteristics on avalanche runout: forest
type, crown closure, vertical structure and surface cover, for
example, values for K were higher for dense spruce and mixed spruce-beech
forests compared to open larch forests at the upper treeline. Considering
forest structural conditions within avalanche simulations will improve
current applications for avalanche simulation tools in mountain forest and
natural hazard management.

http://www.nat-hazards-earth-syst-sci.net/14/2233/2014/ 2014/08/29 - 02:07

Non-susceptible landslide areas in Italy and in the Mediterranean regionNatural Hazards and Earth System Science, 14, 2215-2231, 2014Author(s): I. Marchesini, F. Ardizzone, M. Alvioli, M. Rossi, and F. GuzzettiWe used landslide information for 13 study areas in Italy and morphometric
information obtained from the 3-arcseconds shuttle radar topography mission digital elevation model (SRTM DEM) to determine areas where
landslide susceptibility is expected to be negligible in Italy and in the
landmasses surrounding the Mediterranean Sea. The morphometric information
consisted of the local terrain slope which was computed in a square 3 × 3-cell
moving window, and in the regional relative relief computed in a circular
15 × 15-cell moving window. We tested three different models to
classify the "non-susceptible" landslide areas, including a linear model
(LNR), a quantile linear model (QLR), and a quantile, non-linear model (QNL).
We tested the performance of the three models using independent landslide
information presented by the Italian Landslide Inventory
(Inventario Fenomeni Franosi in Italia – IFFI). Best results were
obtained using the QNL model. The corresponding zonation of
non-susceptible landslide areas was intersected in a geographic information system (GIS) with
geographical census data for Italy. The result determined that 57.5% of
the population of Italy (in 2001) was located in areas where landslide
susceptibility is expected to be negligible. We applied the QNL model to the
landmasses surrounding the Mediterranean Sea, and we tested the synoptic
non-susceptibility zonation using independent landslide information for three
study areas in Spain. Results showed that the QNL model was capable of
determining where landslide susceptibility is expected to be negligible in
the validation areas in Spain. We expect our results to be applicable in
similar study areas, facilitating the identification of non-susceptible
landslide areas, at the synoptic scale.

http://www.nat-hazards-earth-syst-sci.net/14/2215/2014/ 2014/08/29 - 02:07

Developing an index for heavy convective rainfall forecasting over a Mediterranean coastal areaNatural Hazards and Earth System Science, 14, 2205-2214, 2014Author(s): M. Korologou, H. Flocas, and H. MichalopoulouHeavy convective rainfall incidents that occurred over western coastal Greece
and led to flash floods are analyzed with respect to mesoscale analysis for
the period from January 2006 to June 2011. The synoptic scale circulation is
examined throughout the troposphere along with satellite images, lightning
data and synoptic observations of weather stations. Well-known instability
indices are calculated and tested against synoptic observations. Taking into
account the severity of the incidents, the performance of the indices was not
as good as expected. Further detailed analysis resulted in the development of
a new index that incorporates formalized experience of local weather and
modeled knowledge of mechanisms of severe thunderstorms. The proposed index
named Local Instability Index (LII), is then evaluated and its performance is
found to be quite satisfactory.

http://www.nat-hazards-earth-syst-sci.net/14/2205/2014/ 2014/08/29 - 02:07

Comment on "Rip current related drowning deaths and rescues in Australia 2004–2011" by Brighton et al. (2013)Natural Hazards and Earth System Science, 14, 2203-2204, 2014Author(s): B. C. Brewster and R. GouldNo abstract available.

http://www.nat-hazards-earth-syst-sci.net/14/2203/2014/ 2014/08/29 - 02:07

Medicanes in an ocean–atmosphere coupled regional climate modelNatural Hazards and Earth System Science, 14, 2189-2201, 2014Author(s): N. Akhtar, J. Brauch, A. Dobler, K. Béranger, and B. AhrensSo-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and
warm-core Mediterranean cyclones that exhibit some similarities to tropical
cyclones. The strong cyclonic winds associated with medicanes threaten the
highly populated coastal areas around the Mediterranean basin. To reduce the
risk of casualties and overall negative impacts, it is important to improve
the understanding of medicanes with the use of numerical models. In this
study, we employ an atmospheric limited-area model (COSMO-CLM) coupled with
a one-dimensional ocean model (1-D NEMO-MED12) to simulate medicanes. The aim
of this study is to assess the robustness of the coupled model in simulating
these extreme events. For this purpose, 11 historical medicane events are
simulated using the atmosphere-only model, COSMO-CLM, and coupled model, with
different setups (horizontal atmospheric grid spacings of 0.44, 0.22, and
0.08°; with/without spectral nudging, and an ocean grid spacing of
1/12°). The results show that at high resolution, the coupled model is
able to not only simulate most of medicane events but also improve the track
length, core temperature, and wind speed of simulated medicanes compared to
the atmosphere-only simulations. The results suggest that the coupled model
is more proficient for systemic and detailed studies of historical medicane
events, and that this model can be an effective tool for future projections.

http://www.nat-hazards-earth-syst-sci.net/14/2189/2014/ 2014/08/26 - 18:30

The efficiency of the Weather Research and Forecasting (WRF) model for simulating typhoonsNatural Hazards and Earth System Science, 14, 2179-2187, 2014Author(s): T. Haghroosta, W. R. Ismail, P. Ghafarian, and S. M. BarekatiThe Weather Research and Forecasting (WRF) model includes various configuration
options related to physics parameters, which can affect the performance of
the model. In this study, numerical experiments were conducted to determine
the best combination of physics parameterization schemes for the simulation
of sea surface temperatures, latent heat flux, sensible heat flux,
precipitation rate, and wind speed that characterized typhoons. Through
these experiments, several physics parameterization options within the Weather Research and Forecasting
(WRF) model were exhaustively tested for typhoon Noul, which originated in the
South China Sea in November 2008. The model domain consisted of one coarse
domain and one nested domain. The resolution of the coarse domain was 30 km,
and that of the nested domain was 10 km. In this study, model simulation
results were compared with the Climate Forecast System Reanalysis (CFSR)
data set. Comparisons between predicted and control data were made through
the use of standard statistical measurements. The results facilitated the
determination of the best combination of options suitable for predicting
each physics parameter. Then, the suggested best combinations were examined
for seven other typhoons and the solutions were confirmed. Finally, the best
combination was compared with other introduced combinations for wind-speed
prediction for typhoon Washi in 2011. The contribution of this study is to
have attention to the heat fluxes besides the other parameters. The outcomes
showed that the suggested combinations are comparable with the ones in the literature.

http://www.nat-hazards-earth-syst-sci.net/14/2179/2014/ 2014/08/26 - 18:30

Application and prospect of a high-resolution remote sensing and geo-information system in estimating earthquake casualtiesNatural Hazards and Earth System Science, 14, 2165-2178, 2014Author(s): T. Feng, Z. Hong, Q. Fu, S. Ma, X. Jie, H. Wu, C. Jiang, and X. TongAn accurate estimation of a casualty rate is critical in response to
earthquake disasters, and could allow an increase in the survival rate.
Building damage is considered to be a major cause of earthquake casualties in
developing countries. High-resolution satellite imagery (HRSI) can be used to
detect the building damage in a period of a short time. This makes it
possible to use a model to estimate earthquake casualties immediately after
the occurrence of an earthquake. With respect to the capability of HRSI, this
study built a new model for estimating the casualty rate in an earthquake
disaster based on remote sensing and a geographical information system. Three
groups of earthquake data, the 2003 Bam earthquake, the 2008 Wenchuan
earthquake, and the 2010 Yushu earthquake, were used to evaluate this model.
The results indicated that our new model significantly improved the accuracy
in predicting the casualty rate. The parameters used in the model vary
between developed and developing countries. This study could provide valuable
information for a more efficient rescue operation in response to earthquakes.

http://www.nat-hazards-earth-syst-sci.net/14/2165/2014/ 2014/08/26 - 18:30

Brief Communication: CATALYST – a multi-regional stakeholder think tank for fostering capacity development in disaster risk reduction and climate change adaptationNatural Hazards and Earth System Science, 14, 2157-2163, 2014Author(s): M. P. Hare, C. van Bers, P. van der Keur, H. J. Henriksen, J. Luther, C. Kuhlicke, F. Jaspers, C. Terwisscha van Scheltinga, J. Mysiak, E. Calliari, K. Warner, H. Daniel, J. Coppola, and P. F. McGrathThis brief communication presents the work and objectives of the CATALYST
project on "Capacity Development for Hazard Risk Reduction and Adaptation"
funded by the European Commission (October 2011–September 2013). CATALYST
set up a multi-regional think tank covering four regions (Central America and
the Caribbean, East and West Africa, the European Mediterranean, and South
and Southeast Asia), intending to strengthen capacity development for
stakeholders involved in disaster risk reduction (DRR) and climate change
adaptation, in the context of natural hazards. This communication concludes
with a selection of recommendations for capacity development in DRR and
climate change adaptation from the perspective of governance issues.

http://www.nat-hazards-earth-syst-sci.net/14/2157/2014/ 2014/08/22 - 19:43

Automated classification of the atmospheric circulation patterns that drive regional wave climatesNatural Hazards and Earth System Science, 14, 2145-2155, 2014Author(s): J. Pringle, D. D. Stretch, and A. BárdossyWave climates are fundamental drivers of coastal vulnerability;
changing trends in wave heights, periods and directions can severely impact a
coastline. In a diverse storm environment, the changes in these parameters
are difficult to detect and quantify. Since wave climates are linked to
atmospheric circulation patterns, an automated and objective classification
scheme was developed to explore links between synoptic-scale circulation
patterns and wave climate variables, specifically wave heights. The algorithm
uses a set of objective functions based on wave heights to guide the
classification and find atmospheric classes with strong links to wave
behaviour. Spatially distributed fuzzy numbers define the classes and are
used to detect locally high- and low-pressure anomalies. Classes are derived
through a process of simulated annealing. The optimized classification
focuses on extreme wave events. The east coast of South Africa was used as a
case study. The results show that three dominant patterns drive extreme wave
events. The circulation patterns exhibit some seasonality with one pattern
present throughout the year. Some 50–80% of the extreme wave events are
explained by these three patterns. It is evident that strong low-pressure
anomalies east of the country drive a wind towards the KwaZulu-Natal
coastline which results in extreme wave conditions. We conclude that the
methodology can be used to link circulation patterns to wave heights within a
diverse storm environment. The circulation patterns agree with qualitative
observations of wave climate drivers. There are applications to the
assessment of coastal vulnerability and the management of coastlines worldwide.

http://www.nat-hazards-earth-syst-sci.net/14/2145/2014/ 2014/08/22 - 19:43