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Natural Hazards and Earth System Sciences (NHESS)

The CASA quantitative precipitation estimation system: a five year validation studyNatural Hazards and Earth System Science, 12, 2811-2820, 2012Author(s): V. Chandrasekar, Y. Wang, and H. ChenFlooding is one of the most common natural hazards that produce substantial
loss of life and property. The QPE products that are derived at high
spatiotemporal resolution, which is enabled by the deployment of a dense
radar network, have the potential to improve the prediction of
flash-flooding threats when coupled with hydrological models. The US
National Science Foundation Engineering Research Center for Collaborative
Adaptive Sensing of the Atmosphere (CASA) is dedicated to revolutionizing our
ability to observe, understand, predict, and respond to hazardous weather
events, especially in the lower atmosphere. CASA's technology enables
precipitation observation close to the ground and QPE is one of the
important products generated by the system. This paper describes the CASA
QPE system built on the various underlying technologies of networked X-band
radar systems providing high-resolution (in space and time) measurements,
using the rainfall products from the radar. Evaluation of the networked
rainfall product using 5 yr of data from the CASA IP-1 test bed is
presented. Cross validation of the product using 5 yr of data with a
gauge network is also provided. The validation shows the excellent
performance of the CASA QPE system with a standard error of 25% and a low
bias of 3.7%. Examples of various CASA rainfall products including
instantaneous and hourly rainfall accumulations are shown. 2012/09/12 - 22:03

Daily precipitation concentration across Europe 1971–2010Natural Hazards and Earth System Science, 12, 2799-2810, 2012Author(s): N. Cortesi, J. C. Gonzalez-Hidalgo, M. Brunetti, and J. Martin-VideDaily Precipitation Concentration Index (CI) was used in this paper to investigate the statistical structure of
daily precipitation across Europe based on 530 daily rainfall series for the period 1971–2010. Annual CI shows a North-West
to South-East gradient (excluding Turkey and Greece). The same gradient is also observed in winter, spring and autumn,
while in summer the gradient is North-South. Highest annual and seasonal daily concentrations of rainfall were detected
in the western Mediterranean basin, mainly along Spanish and French coastlands. Latitude and distance from the sea seems
to play a major role on spatial CI distribution; at subregional scale also relief plays an important role.
The Mann–Kendall test did not identify uniform significant pattern in temporal trend across Europe for 1971–2010 period.
The only broad areas with increasing annual and seasonal CI values are located in northern and south-western
France and northern coastlands of the Iberian Peninsula. This findings suggest that daily precipitation distribution
has not significantly changed during the 1971–2010 over Europe. 2012/09/11 - 20:26

Improving the active involvement of stakeholders and the public in flood risk management – tools of an involvement strategy and case study results from Austria, Germany and ItalyNatural Hazards and Earth System Science, 12, 2785-2798, 2012Author(s): M. Fleischhauer, S. Greiving, F. Flex, M. Scheibel, T. Stickler, N. Sereinig, G. Koboltschnig, P. Malvati, V. Vitale, P. Grifoni, and K. FirusThe EU Flood Risk Management Directive 2007/60/EC aims at an active
involvement of interested parties in the setting up of flood risk management
plans and thus calls for more governance-related decision-making. This
requirement has two perspectives. On the one hand, there is (1) the question
of how decision-makers can improve the quality of their governance process. On
the other hand, there is (2) the question of how the public shall be
appropriately informed and involved. These questions were the centre of
the ERA-Net CRUE-funded project IMRA (integrative flood risk governance
approach for improvement of risk awareness) that aimed at an optimisation of
the flood risk management process by increasing procedural efficiency with
an explicit involvement strategy. To reach this goal, the IMRA project
partners developed two new approaches that were implemented in three case
study areas for the first time in flood risk management:

1. risk governance assessment tool: An indicator-based benchmarking and
monitoring tool was used to evaluate the performance of a flood risk management
system in regard to ideal risk governance principles;

2. social milieu approach: The concept of social milieus was used to gain
a picture of the people living in the case study regions to learn more about
their lifestyles, attitudes and values and to use this knowledge to plan
custom-made information and participation activities for the broad public.

This paper presents basic elements and the application of two innovative
approaches as a part of an "involvement strategy" that aims at the active
involvement of all interested parties (stakeholders) for assessing,
reviewing and updating flood risk management plans, as formulated in the EU
Flood Risk Management Directive 2007/60/EC. 2012/09/11 - 20:26

Dynamical and statistical downscaling of the French Mediterranean climate: uncertainty assessmentNatural Hazards and Earth System Science, 12, 2769-2784, 2012Author(s): M. Vrac, P. Drobinski, A. Merlo, M. Herrmann, C. Lavaysse, L. Li, and S. SomotERA-40 reanalyses, and simulations from three regional climate models (RCMs) (ALADIN, LMDZ, and WRF)
and from one statistical downscaling model (CDF-t) are used to evaluate the uncertainty in downscaling of wind, temperature,
and rainfall cumulative distribution functions (CDFs) for eight stations in the French Mediterranean basin over 1991–2000. The
uncertainty is quantified using the Cramer-von Mises score (CvM) to measure the "distance" between the simulated and observed CDFs.
The ability of the three RCMs and CDF-t to simulate the "climate" variability is quantified with the explained variance, variance ratio and extreme occurrence.
The study shows that despite their differences, the three RCMs display very similar performance. In terms of global distributions (i.e. CvM), all models
perform better than ERA-40 for both seasons and variables. However, looking at variance criteria, RCMs are not always much better than ERA-40 reanalyses, whereas
CDF-t produces accurate results when applied to ERA-40.
In a second step, a combined statistical/dynamical downscaling approach has been used, consisting in applying CDF-t to the RCM outputs. It shows that CDF-t
applied to the RCM outputs does not necessarily produce better results than those from CDF-t directly applied to ERA-40. It also shows that CDF-t applied to RCMs
generally improves the downscaled CDFs and that the "additional" added value of CDF-t applied to the RCMs is independent of the performance of the RCMs in
terms of CvM, explained variance, variance ratio and extreme occurrence. 2012/09/06 - 17:58

Assessment of liquefaction potential index for Mumbai cityNatural Hazards and Earth System Science, 12, 2759-2768, 2012Author(s): J. Dixit, D. M. Dewaikar, and R. S. JangidMumbai city is the financial capital of India and is fifth most densely
populated city in the world. Seismic soil liquefaction is evaluated for
Mumbai city in terms of the factors of safety against liquefaction (FS) along
the depths of soil profiles for different earthquakes with 2% probability
of exceedance in 50 yr using standard penetration test (SPT)-based
simplified empirical procedure. This liquefaction potential is evaluated at
142 representative sites in the city using the borehole records from
standard penetration tests. Liquefaction potential index (LPI) is evaluated at
each borehole location from the obtained factors of safety (FS) to predict the
potential of liquefaction to cause damage at the surface level at the site
of interest. Spatial distribution of soil liquefaction potential is
presented in the form of contour maps of LPI values. As the majority of the sites
in the city are of reclaimed land, the vulnerability of liquefaction is
observed to be very high at many places. 2012/09/06 - 17:58

Fire cue effects on seed germination of six species of northwestern Patagonian grasslandsNatural Hazards and Earth System Science, 12, 2753-2758, 2012Author(s): S. L. Gonzalez and L. GhermandiPostfire recruitment of seedlings has been attributed to a stimulation of
germination by fire-related cues. The germination response to heat shock
(80 °C – 5 min), smoke (60 min), the combination of both factors
and no heat no smoke (control) was studied in six native species (two
dominant grasses, two dominant shrubs and two annual fugitive herbs) of
northwestern Patagonian grasslands. Seeds of the grasses Festuca
pallescens and Stipa speciosa and the shrub Senecio
bracteolatus (Asteraceae) germinated when they were exposed to heat shock,
whereas seeds of the other shrub, Mulinum spinosum (Apiaceae), were
killed by this fire cue. In grasses, probably the glume of caryopsis
protected embryos from heat. Possibly, the seed size could explain the
different responses of the two shrubs. Heat combined with smoke reduced seed
germination for S. speciosa and S. bracteolatus. The heat could
have scarified seeds and the longer exposure to smoke could have been toxic
for embryos. The same treatment increased germination of the annual fugitive
herb Boopis gracilis (Calyceraceae). We
concluded that fire differentially affects the seedling recruitment of the
studied species in the northwestern Patagonian grasslands. 2012/09/06 - 17:58

A hydrological analysis of the 4 November 2011 event in GenoaNatural Hazards and Earth System Science, 12, 2743-2752, 2012Author(s): F. Silvestro, S. Gabellani, F. Giannoni, A. Parodi, N. Rebora, R. Rudari, and F. SiccardiOn the 4 November 2011 a flash flood event hit the area of Genoa with
dramatic consequences. Such an event represents, from the meteorological and
hydrological perspective, a paradigm of flash floods in the Mediterranean

The hydro-meteorological probabilistic forecasting system for small and
medium size catchments in use at the Civil Protection Centre of Liguria
region exhibited excellent performances for the event, by predicting, 24–48 h
in advance, the potential level of risk associated with the forecast. It
greatly helped the decision makers in issuing a timely and correct alert.

In this work we present the operational outputs of the system provided
during the Liguria events and the post event hydrological modelling analysis
that has been carried out accounting also for the crowd sourcing information
and data. We discuss the benefit of the implemented probabilistic systems
for decision-making under uncertainty, highlighting how, in this case, the
multi-catchment approach used for predicting floods in small basins has been
crucial. 2012/09/03 - 14:09

Urban modelling for seismic prone areas: the case study of Vila Franca do Campo (Azores Archipelago, Portugal)Natural Hazards and Earth System Science, 12, 2731-2741, 2012Author(s): V. N. Martins, P. Cabral, and D. Sousa e SilvaSeismic risk mitigation comprises of land-use planning policies that enable
risk reduction in areas exposed to earthquakes. Thus, the assessment of
land-use plans regarding urban growth in seismic prone areas is very
important. This article analyses the urban expansion of Vila Franca do Campo
(island of S. Miguel, Azores, Portugal) from 1994 to 2005 based on
ortophotomaps interpretations and simulates a scenario of urban growth for
the year 2016 with a Land-use and Cover-Change (LUCC) model (Geomod). The goal
is to evaluate the potential impact of land-use plans in managing urban
growth and promoting seismic risk mitigation. Results indicate that the
urban expansion, between 1994 and 2005, was done according to the Municipal
Master Plan (MMP) restrictions. The scenario modelled for the year 2016 is
potentially stricter for urban growth because it adds to the previous plan
the constraints defined by the South Coast Management Plan (SCMP) that
entered into force in 2007. In both time periods, a continuing urban growth
towards seismic areas was identified. The absence of seismic risk mitigation
policies and measures on both plans may contribute to increase the seismic
hazard exposure and vulnerability. The results of this study strongly
suggest the reformulation of future land-use plans to include seismic risk
mitigation goals and policies. 2012/09/03 - 14:09

Rainfall and earthquake-induced landslide susceptibility assessment using GIS and Artificial Neural NetworkNatural Hazards and Earth System Science, 12, 2719-2729, 2012Author(s): Y. Li, G. Chen, C. Tang, G. Zhou, and L. ZhengA GIS-based method for the assessment of landslide susceptibility in a
selected area of Qingchuan County in China is proposed by using the
back-propagation Artificial Neural Network model (ANN). Landslide inventory
was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as
rainfall-induced landslides (RIL) in this study), and 885 earthquake-induced
landslides (EIL) were recorded into the landslide inventory map. To
understand the different impacts of rainfall and earthquake on landslide
occurrence, we first compared the variations between landslide spatial
distribution and conditioning factors. Then, we compared the weight variation
of each conditioning factor derived by adjusting ANN structure and factors
combination respectively. Last, the weight of each factor derived from the
best prediction model was applied to the entire study area to produce
landslide susceptibility maps.

Results show that slope gradient has the highest weight for landslide
susceptibility mapping for both RIL and EIL. The RIL model built with four
different factors (slope gradient, elevation, slope height and distance to
the stream) shows the best success rate of 93%; the EIL model built with
five different factors (slope gradient, elevation, slope height, distance to
the stream and distance to the fault) has the best success rate of 98%.
Furthermore, the EIL data was used to verify the RIL model and the success
rate is 92%; the RIL data was used to verify the EIL model and the
success rate is 53%. 2012/08/31 - 16:59

Structural damages observed in state buildings after Simav/Turkey earthquake occurred on 19 May 2011Natural Hazards and Earth System Science, 12, 2709-2718, 2012Author(s): Y. S. TamaDifferent levels of damages occurred in state buildings, especially in
educational facilities, during the Simav earthquake (ML=5.7) on
19 May 2011. A site survey was carried out in the area after the earthquake, where
six state buildings were examined in detail. The results of the survey
showed that main reasons for the formation of damages in these buildings are
the use of low strength concrete, insufficient reinforcement, inappropriate
detailing, and low-quality workmanship. The investigated buildings were also
evaluated by P25-rapid assessment method. The method demonstrates that two
of the buildings in question are in "high risk band"; the other two fall
into "detailed evaluation band", and the rest are in the "low risk band".
This figure also matches with the damages observed in the site survey. 2012/08/27 - 21:23

Multivariate return periods of sea storms for coastal erosion risk assessmentNatural Hazards and Earth System Science, 12, 2699-2708, 2012Author(s): S. Corbella and D. D. StretchThe erosion of a beach depends on various storm characteristics. Ideally, the
risk associated with a storm would be described by a single multivariate
return period that is also representative of the erosion risk, i.e. a 100 yr
multivariate storm return period would cause a 100 yr erosion return period.
Unfortunately, a specific probability level may be associated with numerous
combinations of storm characteristics. These combinations, despite having the
same multivariate probability, may cause very different erosion outcomes.
This paper explores this ambiguity problem in the context of copula based
multivariate return periods and using a case study at Durban on the east
coast of South Africa. Simulations were used to correlate multivariate return
periods of historical events to return periods of estimated storm induced
erosion volumes. In addition, the relationship of the most-likely design event
(Salvadori et al., 2011) to coastal erosion was investigated. It was found that
the multivariate return periods for wave height and duration had the highest
correlation to erosion return periods. The most-likely design event was found
to be an inadequate design method in its current form. We explore the
inclusion of conditions based on the physical realizability of wave events
and the use of multivariate linear regression to relate storm parameters to
erosion computed from a process based model. Establishing a link between
storm statistics and erosion consequences can resolve the ambiguity between
multivariate storm return periods and associated erosion return periods. 2012/08/24 - 22:48

Developing Tsunami fragility curves using remote sensing and survey data of the 2010 Chilean Tsunami in DichatoNatural Hazards and Earth System Science, 12, 2689-2697, 2012Author(s): E. Mas, S. Koshimura, A. Suppasri, M. Matsuoka, M. Matsuyama, T. Yoshii, C. Jimenez, F. Yamazaki, and F. ImamuraOn 27 February 2010, a megathrust earthquake of Mw = 8.8 generated a
destructive tsunami in Chile. It struck not only Chilean coast but propagated all the way to Japan.
After the event occurred, the post-tsunami survey team was assembled, funded by the Japan Science and Technology Agency (JST),
to survey the area severely affected by the tsunami. The tsunami damaged and destroyed numerous houses, especially in the town of Dichato.
In order to estimate the structural fragility against tsunami hazard in this area, tsunami fragility curves were developed. Surveyed
data of inundation depth and visual inspection of satellite images of Dichato were used to classify the damage to housing. A practical
method suitable when there are limitations on available data for numerical simulation or damage evaluation from surveys is presented
here. This study is the first application of tsunami fragility curves on the South American Pacific coast and it might be of practical
use for communities with similar characteristics along the west Pacific coast. The proposed curve suggests that structures in
Dichato will be severely damaged – with a 68% probability – already at 2 m tsunami inundation depth. 2012/08/24 - 22:48

Heavy precipitation events in the Mediterranean: sensitivity to cloud physics parameterisation uncertaintiesNatural Hazards and Earth System Science, 12, 2671-2688, 2012Author(s): S. Fresnay, A. Hally, C. Garnaud, E. Richard, and D. LambertIn autumn, southeastern France is often affected by heavy precipitation
events which may result in damaging flash-floods. The 20 October and
1 November 2008 are two archetypes of the meteorological situations under
which these events occur: an upper-level trough directing a warm and moist
flow from the Mediterranean towards the Cévennes ridge or a quasi
stationary meso-scale convective complex developing over the Rhone valley.
These two types of events exhibit a contrasting level of predictability; the
former being usually better forecast than the latter. Control experiments
performed with the Meso-NH model run with a 2.5 km resolution confirm these
predictability issues. The deterministic forecast of the November case
(Cévennes ridge) is found to be much more skilful than the one for the
October case (Rhone valley). These two contrasting situations are used to
investigate the sensitivity of the model for cloud physics parameterisation
uncertainties. Three 9-member ensembles are constructed. In the first one,
the rain distribution intercept parameter is varied within its range of
allowed values. In the second one, random perturbations are applied to the
rain evaporation rate, whereas in the third one, random perturbations are
simultaneously applied to the cloud autoconversion, rain accretion, and rain
evaporation rates. Results are assessed by comparing the time and space
distribution of the observed and forecasted precipitation. For the Rhone
valley case, it is shown that not one of the ensembles is able to drastically
improve the skill of the forecast. Taylor diagrams indicate that the
microphysical perturbations are more efficient in modulating the rainfall
intensities than in altering their localization. Among the three ensembles,
the multi-process perturbation ensemble is found to yield the largest spread
for most parameters. In contrast, the results of the Cévennes case exhibit
almost no sensitivity to the microphysical perturbations. These
results clearly show that the usefulness of an ensemble prediction system
based upon microphysical perturbations is case dependent. Additional
experiments indicate a greater potential for the multi-process ensemble when
the model resolution is increased to 500 m. 2012/08/24 - 22:48

A lightning climatology of the South-West Indian OceanNatural Hazards and Earth System Science, 12, 2659-2670, 2012Author(s): C. Bovalo, C. Barthe, and N. BègueThe World Wide Lightning Location Network (WWLLN) data have been used to
perform a lightning climatology in the South-West Indian Ocean (SWIO) region
from 2005 to 2011. Maxima of lightning activity were found in the Maritime
Continent and southwest of Sri Lanka (>50 fl km−2 yr−1)
but also over Madagascar and above the Great Lakes of East Africa
(>10–20 fl km−2 yr−1). Lightning flashes within tropical
storms and tropical cyclones represent 50 % to 100 % of the total
lightning activity in some oceanic areas of the SWIO (between 10° S
and 20° S).

The SWIO is characterized by a wet season (November to April) and a dry
season (May to October). As one could expect, lightning activity is more
intense during the wet season as the Inter Tropical Convergence Zone (ITCZ) is present over all the basin.
Flash density is higher over land in November–December–January with values
reaching 3–4 fl km−2 yr−1 over Madagascar. During the dry
season, lightning activity is quite rare between 10° S and
25° S. The Mascarene anticyclone has more influence on the SWIO
resulting in shallower convection. Lightning activity is concentrated over
ocean, east of South Africa and Madagascar.

A statistical analysis has shown that El Niño–Southern Oscillation mainly
modulates the lightning activity up to 56.8% in the SWIO. The Indian Ocean
Dipole has a significant contribution since ~49% of the variability
is explained by this forcing in some regions. The Madden–Julian Oscillation
did not show significative impact on the lightning activity in our study. 2012/08/23 - 00:47

Socio-economic vulnerability of coastal communities in southern Thailand: the development of adaptation strategiesNatural Hazards and Earth System Science, 12, 2647-2658, 2012Author(s): P. Willroth, F. Massmann, R. Wehrhahn, and J. Revilla DiezThe tsunami of December 2004 impacted large areas of Thailand's coastline and
caused severe human and economic losses. The recovery period revealed
differences in the vulnerabilities of communities affected. An understanding
of the causal factors of vulnerability is crucial for minimising the negative
effects of future threats and developing adaptive capacities. This paper
analyses the vulnerabilities and the development of adaptation strategies in
the booming tourist area of Khao Lak and in the predominantly fishing and
agricultural area of Ban Nam Khem through a comprehensive vulnerability
framework. The results show that social networks played a crucial role in
coping with the disaster. Social cohesion is important for strengthening the
community and developing successful adaptation strategies. The development of
tourism and the turning away from traditional activities have a significant
positive influence on the income situation, but create a dependency on a
single business sector. It could be shown that households generating their
income in the tourism sector were vulnerable unless they had diversified
their income previously. Income diversification decreased the vulnerability
in the study areas. Adaptation strategies and processes developed in the
aftermath clearly address these issues. 2012/08/23 - 00:47

Hydro-meteorological evaluation of a convection-permitting ensemble prediction system for Mediterranean heavy precipitating eventsNatural Hazards and Earth System Science, 12, 2631-2645, 2012Author(s): B. Vié, G. Molinié, O. Nuissier, B. Vincendon, V. Ducrocq, F. Bouttier, and E. RichardAn assessment of the performance of different convection-permitting ensemble
prediction systems (EPSs) is performed, with a focus on Heavy Precipitating
Events (HPEs). The convective-scale EPS configuration includes perturbations
of lateral boundary conditions (LBCs) by using a global ensemble to provide
LBCs, initial conditions (ICs) through an ensemble data assimilation
technique and perturbations of microphysical parameterisations to account
for part of model errors. A probabilistic evaluation is conducted over an
18-day period. A clear improvement is found when uncertainties on LBCs and
ICs are considered together, but the chosen microphysical perturbations have
no significant impact on probabilistic scores.

Innovative evaluation processes for three HPE case studies are implemented.
First, maxima diagrams provide a multi-scale analysis of intense rainfall.
Second, an hydrological evaluation is performed through the computation of
discharge forecasts using hourly ensemble precipitation forecasts as an
input. All ensembles behave similarly, but differences are found highlighting
the impact of microphysical perturbations on HPEs forecasts, especially for
cases involving complex small-scale processes. 2012/08/22 - 04:03

Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian OceanNatural Hazards and Earth System Science, 12, 2609-2630, 2012Author(s): J. M. Schwab, S. Krastel, M. Grün, F. Gross, P. Pananont, P. Jintasaeranee, S. Bunsomboonsakul, W. Weinrebe, and D. Winkelmann2-D seismic data from the top and the western slope of Mergui Ridge in water
depths between 300 and 2200 m off the Thai west coast have been investigated
in order to identify mass transport deposits (MTDs) and evaluate the
tsunamigenic potential of submarine landslides in this outer shelf area.
Based on our newly collected data, 17 mass transport deposits have been
identified. Minimum volumes of individual MTDs range between 0.3 km3
and 14 km3. Landslide deposits have been identified in three different
settings: (i) stacked MTDs within disturbed and faulted basin sediments at
the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within
a pile of drift sediments at the basin-ridge transition; and (iii) MTDs
near the edge of/on top of Mergui Ridge in relatively shallow water depths
(< 1000 m). Our data indicate that the Mergui Ridge slope area seems to have
been generally unstable with repeated occurrence of slide events. We find
that the most likely causes for slope instabilities may be the presence of
unstable drift sediments, excess pore pressure, and active tectonics. Most
MTDs are located in large water depths (> 1000 m) and/or comprise small
volumes suggesting a small tsunami potential. Moreover, the recurrence rates
of failure events seem to be low. Some MTDs with tsunami potential, however,
have been identified on top of Mergui Ridge. Mass-wasting events that may
occur in the future at similar locations may trigger tsunamis if they
comprise sufficient volumes. Landslide tsunamis, emerging from slope
failures in the working area and affecting western Thailand coastal areas
therefore cannot be excluded, though the probability is very small compared
to the probability of earthquake-triggered tsunamis, arising from the Sunda
Trench. 2012/08/17 - 13:51

Testing the critical exponent in the relation between stress drop of earthquake and lead time of seismic electric signalNatural Hazards and Earth System Science, 12, 2603-2607, 2012Author(s): E. DologlouThe application of new data in the power law relation between the stress
drop of the earthquake and the lead time of the precursory seismic electric
signal led to an exponent which falls in the range of the values of
critical exponents for fracture and it is in excellent agreement with a
previous one found by (Dologlou, 2012). In addition, this exponent is very
close to the one reported by Varotsos and Alexopoulos (1984a), which
interconnects the amplitude of the precursory seismic electric signals (SES)
and the magnitude of the impending earthquake. Hence, the hypothesis that
underlying dynamic processes evolving to criticality prevail in the pre-focal area when the SES is emitted is significantly supported. 2012/08/16 - 16:45

Long-term temporal changes in the occurrence of a high forest fire danger in FinlandNatural Hazards and Earth System Science, 12, 2591-2601, 2012Author(s): H. M. Mäkelä, M. Laapas, and A. VenäläinenClimate variation and change influence several ecosystem components
including forest fires. To examine long-term temporal variations of forest
fire danger, a fire danger day (FDD) model was developed. Using mean
temperature and total precipitation of the Finnish wildfire season
(June–August), the model describes the climatological preconditions of fire
occurrence and gives the number of fire danger days during the same time
period. The performance of the model varied between different regions in
Finland being best in south and west. In the study period 1908–2011, the
year-to-year variation of FDD was large and no significant increasing or
decreasing tendencies could be found. Negative slopes of linear regression
lines for FDD could be explained by the simultaneous, mostly not significant
increases in precipitation. Years with the largest wildfires did not stand
out from the FDD time series. This indicates that intra-seasonal variations
of FDD enable occurrence of large-scale fires, despite the whole season's
fire danger is on an average level. Based on available monthly climate data,
it is possible to estimate the general fire conditions of a summer. However,
more detailed input data about weather conditions, land use, prevailing
forestry conventions and socio-economical factors would be needed to gain
more specific information about a season's fire risk. 2012/08/16 - 16:45

Measurement frequency and sampling spatial domains required to characterize turbidity and salinity events in the Guadalquivir estuary (Spain)Natural Hazards and Earth System Science, 12, 2581-2589, 2012Author(s): E. Contreras and M. J. PoloEstuaries are complex systems in which long water quality data series are
not always available at the proper scale. Data proceeding from several water
quality networks, with different measuring frequencies (monthly, weekly and
15 min) and different numbers of sampling points, were compared throughout
the main channel of the Guadalquivir estuary. Higher frequency of turbidity
sampling in the upper estuary is required. In the lower estuary, sampling
points help to find out the ETM, and higher frequency sampling of EC is
required because of the effect of the tidal and river components. This could
be a feedback for the implementation of monitoring networks in estuaries. 2012/08/14 - 22:25

Geological evidence for paleotsunamis along eastern Sicily (Italy): an overviewNatural Hazards and Earth System Science, 12, 2569-2580, 2012Author(s): P. M. De Martini, M. S. Barbano, D. Pantosti, A. Smedile, C. Pirrotta, P. Del Carlo, and S. PinziWe present geological evidence for paleotsunamis along the ~230 km-long
coast of eastern Sicily (Italy); combining this information
with historical data, we reconstruct a unique history of tsunami inundations.
We integrate data on 38 paleotsunami deposits (from fine sand layers to
boulders) collected at 11 sites (one offshore). The geological data record
traces of large tsunamis which have occurred during the past 4 millennia. Chronological
constrains include 14C, 210Pb and 137Cs, OSL and
tephrochronology. When compatible, the age of the paleotsunami deposits is
associated to historical events, but it is also used to highlight unknown
tsunamis. Average tsunami recurrence interval (between 320 and 840 yr) and
minimum inland tsunami ingressions (often greater than the historical ones)
were estimated at several sites. On the basis of this work, the tsunami
catalogue is implemented by two unknown tsunamis which occurred during the first
millennium BC and by one unknown regional tsunami, which occurred in 650–770 AD.
By including this latter event in the eastern Sicily catalogue, we estimate
an average recurrence interval for strong tsunamis of ca. 385 yr.

Comparison and merging of historical and geological data can definitely
contribute to a better understanding of regional and local tsunami potential
and provides robust parameters to be used in tsunami hazard estimates. 2012/08/14 - 22:25

Combining inland and offshore paleotsunamis evidence: the Augusta Bay (eastern Sicily, Italy) case studyNatural Hazards and Earth System Science, 12, 2557-2567, 2012Author(s): A. Smedile, P. M. De Martini, and D. PantostiOffshore and inland geological evidence for multiple tsunami inundations was
found in the Augusta Bay area: (1) the main local historical
tsunamis (1908, 1693, 1169), (2) two far-generated tsunamis (i.e. Crete
365 AD and Santorini, 3600 BP), and (3) seven unknown tsunamis). Average
tsunami recurrence intervals from inland and offshore investigations of
about 550 and 320 yr, respectively were obtained for the past 4 ka. The
history of paleotsunamis from the marine record appears to be as complete as
the historical one for the past millennium, yielding an average tsunami
recurrence interval of 250 yr for the Augusta Bay. Geological data allow
also estimating a minimum tsunami inundation distance of 530 m and a
minimum run-up of 5 m. The marine record contains evidence for more
paleotsunamis with respect to the inland one because of continuous
sedimentation and better preservation of stratigraphy in the offshore with
respect to coastal areas, which are commonly affected by intermittent-erosion and
sedimentation and anthropic activities.

This work shows that the integration of geological and historical data can
provide critical information regarding the extent and age of tsunamis of the
past (e.g. inundation distance, age, and frequency), which is of immediate relevance
for tsunami hazard assessment. 2012/08/14 - 22:25

Relationships between magnetic parameters, chemical composition and clay minerals of topsoils near Coimbra, central PortugalNatural Hazards and Earth System Science, 12, 2545-2555, 2012Author(s): A. M. Lourenço, F. Rocha, and C. R. GomesMagnetic measurements, mineralogical and geochemical studies were carried
out on surface soil samples in order to find possible relationships and to
obtain environmental implications. The samples were taken over a square grid
(500 × 500 m) near the city of Coimbra, in central Portugal. Mass specific
magnetic susceptibility ranges between 12.50 and 710.11 × 10−8 m3 kg−1
and isothermal magnetic remanence at 1 tesla values range
between 253 and 18 174 × 10−3 Am−1. Chemical analysis by atomic
absorption spectrometry shows that the concentration of various toxic
elements was higher than the mean background values for world soils. Higher
values of susceptibility and toxic elements content were reported near roads
and rivers. Urban pollution and road traffic emission seem to be the main
influence for these values. A semi-quantitative X-ray diffraction study has
been carried out on a representative set of subsamples, using peak areas.
Illite (average 52%), kaolinite (average 55%), chlorite (average 6%)
and irregular illite-smectite mixed-layers (average 9%) are the
major clay minerals groups identified. Mineral composition of total fraction
confirms the presence of magnetite/maghemite. The clay minerals results
point to a contrast in the behavior of the main clay minerals: illite,
chlorite, and kaolinite (also, smectite in some samples), which are
generally in agreement with the magnetic and geochemical data. The results
showed that magnetic measurements are a sensitive, fast, inexpensive and
robust method, which can be advantageously applied for studying soils
affected by urban and road pollution. 2012/08/14 - 22:25

Continuous multi-criteria methods for crop and soil conservation planning on La Colacha (Río Cuarto, Province of Córdoba, Argentina)Natural Hazards and Earth System Science, 12, 2529-2543, 2012Author(s): J. M. Antón, J. B. Grau, J. M. Cisneros, F. V. Laguna, P. L. Aguado, J. J. Cantero, D. Andina, and E. SánchezAgro-areas of Arroyos Menores (La Colacha) west and south of Río
Cuarto (Prov. of Córdoba, Argentina) basins are very fertile but have
high soil loses. Extreme rain events, inundations and other severe erosions
forming gullies demand urgently actions in this area to avoid soil
degradation and erosion supporting good levels of agro production. The authors
first improved hydrologic data on La Colacha, evaluated the systems of
soil uses and actions that could be recommended considering the relevant
aspects of the study area and applied decision support systems (DSS)
with mathematic tools for planning of defences and uses of soils in these
areas. These were conducted here using multi-criteria models, in multi-criteria decision making (MCDM); first of discrete MCDM to
chose among global types of use of soils, and then of continuous MCDM to evaluate and optimize combined actions, including repartition of
soil use and the necessary levels of works for soil conservation and for hydraulic management to conserve against erosion these basins.
Relatively global solutions for La Colacha area have been defined and were
optimised by Linear Programming in Goal Programming forms that are
presented as Weighted or Lexicographic Goal Programming and as Compromise
Programming. The decision methods used are described, indicating algorithms
used, and examples for some representative scenarios on La Colacha area are given. 2012/08/14 - 00:23

Decadal trends in beach morphology on the east coast of South Africa and likely causative factorsNatural Hazards and Earth System Science, 12, 2515-2527, 2012Author(s): S. Corbella and D. D. StretchSandy shorelines are dynamic with constant changes that can cause hazards in
developed areas. The causes of change may be either natural or anthropogenic.
This paper evaluates evidence for shoreline changes and their causative
factors using a case study on the east coast of South Africa. Beach
morphology trends were found to be location-specific, but overall the beaches
show a receding trend. It was hypothesized that wave, tide, sea level and
wind trends as well as anthropogenic influences are causative factors, and
their contributions to shoreline changes were evaluated. Maximum significant
wave heights, average wave direction, peak period and storm event frequencies
all show weak increasing trends, but only the increases in peak period and
wave direction are statistically significant. The chronic beach erosion
cannot be attributed to wave climate changes since they are still too small
to explain the observations. Instead, the impacts of sea level rise and
reductions in the supply of beach sediments are suggested as the main
causative factors. The analysis also identifies a trend in the frequency of
severe erosion events due to storms that coincide with a 4.5-yr extreme tide
cycle, which demonstrates the potential impact of future sea level rise. 2012/08/14 - 00:23

Preface "New Developments in Tsunami Science: from Hazard to Risk"Natural Hazards and Earth System Science, 12, 2507-2514, 2012Author(s): I. Didenkulova, S. Monserrat, and S. Tinti 2012/08/14 - 00:23

Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channelNatural Hazards and Earth System Science, 12, 2499-2505, 2012Author(s): N. HottaMeasuring the interstitial water pressure of debris flows under various
conditions gives essential information on the flow stress structure. This
study measured the basal interstitial water pressure during debris flow
routing experiments in a laboratory flume. Because a sensitive pressure
gauge is required to measure the interstitial water pressure in shallow
laboratory debris flows, a differential gas pressure gauge with an attached
diaphragm was used. Although this system required calibration before and
after each experiment, it showed a linear behavior and a sufficiently high
temporal resolution for measuring the interstitial water pressure of debris
flows. The values of the interstitial water pressure were low. However, an
excess of pressure beyond the hydrostatic pressure was observed with
increasing sediment particle size. The measured excess pressure corresponded
to the theoretical excess interstitial water pressure, derived as a Reynolds
stress in the interstitial water of boulder debris flows. Turbulence was
thought to induce a strong shear in the interstitial space of sediment
particles. The interstitial water pressure in boulder debris flows should be
affected by the fine sediment concentration and the phase transition from
laminar to turbulent debris flow; this should be the subject of future
studies. 2012/08/11 - 06:13

Glacial lake mapping with very high resolution satellite SAR dataNatural Hazards and Earth System Science, 12, 2487-2498, 2012Author(s): T. Strozzi, A. Wiesmann, A. Kääb, S. Joshi, and P. MoolFloods resulting from the outbursts of glacial lakes are among the most
far-reaching disasters in high mountain regions. Glacial lakes are typically
located in remote areas and space-borne remote sensing data are an important
source of information about the occurrence and development of such lakes.
Here we show that very high resolution satellite Synthetic Aperture Radar
(SAR) data can be employed for reliably mapping glacial lakes. Results in
the Alps, Pamir and Himalaya using TerraSAR-X and Radarsat-2 data are
discussed in comparison to in-situ information, and high-resolution
satellite optical and radar imagery. The performance of the satellite SAR
data is best during the snow- and ice-free season. In the broader
perspective of hazard management, the detection of glacial lakes and the
monitoring of their changes from very high-resolution satellite SAR
intensity images contributes to the initial assessment of hazards related to
glacial lakes, but a more integrated, multi-level approach needs also to
include other relevant information such as glacier outlines and outline
changes or the identification of unstable slopes above the lake and the
surrounding area, information types to which SAR analysis techniques can also
contribute. 2012/08/08 - 11:14

Relationship between seismicity and water level in the Enguri high dam area (Georgia) using the singular spectrum analysisNatural Hazards and Earth System Science, 12, 2479-2485, 2012Author(s): L. Telesca, T. Matcharasvili, T. Chelidze, and N. ZhukovaThe declustered seismic catalog from 1965 to 2010 around the Enguri high dam
reservoir in western Georgia was analyzed using the singular spectrum
analysis (SSA) technique in order to investigate the relationship of local
seismicity with the reservoir water variations. In particular, the seismic
activity was analyzed in two periods: a "reference" period, from 1965 to
1970, before the start of dam building in 1971; and an "active" period,
from 1978 to 2010, in which the influence of the reservoir was significantly
effective on the seismic activity (since the first flooding of the dam
occurred in 1978). The SSA was applied to both the monthly number of
earthquakes and the time series of the monthly mean of the water level. The
first four reconstructed components explained most of the total variance in
both seismicity and water level. Clear signatures of the annual oscillation
linked with the loading/unloading operations of the dam are present in the
periodogram of the second and the third reconstructed components of the
seismic activity during the "active" period. Such annual cycle is absent
in the periodogram of the reconstructed components of the seismic activity
during the "reference" period. This is a clear indication of the
reservoir-induced character of the seismicity around the Enguri dam. 2012/08/08 - 11:14

Recurring features of extreme autumnall rainfall events on the Veneto coastal areaNatural Hazards and Earth System Science, 12, 2463-2477, 2012Author(s): A. Barbi, M. Monai, R. Racca, and A. M. RossaRecent recurring episodes of heavy flash flood-producing rainfall events on
the Veneto coastal area have renewed the interest in documenting the
frequency and key dynamical ingredients of such events. A climatological
analysis of the precipitation in Veneto reveals that, in comparison with the
rest of the region, the coastal area is characterized by fewer rain days,
lower rainfall accumulations, yet more days with heavy precipitation. If set
in relation to the yearly rainfall, daily accumulation can reach values as
high as 40% of the yearly total rainfall, more regularly between 15%
and 30%, often in periods of 12 h or less.

Four such heavy rainfall events were analyzed and synthetically described to
highlight key ingredients which appear instrumental in producing the high
rainfall accumulations. These comprise an upper-level trough elongating or
cutting off into the Western Mediterranean basin after a period of one to
two weeks of anticyclonic fair weather conditions with temperatures above
normal. The moisture supply over the Adriatic onto north-eastern Italy is
favoured by above normal sea surface temperatures, enhanced advection by a
surface low in the Gulf of Genoa, and in three of the four cases, an
additional surface low over southern Italy. The air flows associated with
the upper-level trough for the cases discussed were of moderate to weak
intensity, and convectively conditionally unstable. The flow intensity was
such that the lower tropospheric portion was blocked by and forced to flow
around the Alpine barrier, i.e. manifesting as a north-easterly, low-level
flow over much of the north-eastern Italian plains. This blocked flow seemed
to interact with the larger-scale synoptic flow to form a distinct and
persistent low-level convergence in the area of the Veneto coast.

It is suggested that these low-level convergence patterns are key in
releasing the convective instability present in the larger-scale flow just
on the Veneto coastal area. Hereby, it is the synoptic rather than the
convective setting which dictated the observed timescales of intense
rainfall. Therefore, the convective rainfall rates paired with the synoptic
durations combine to produce the exceptionally high rainfall accumulations
observed. Cases like these are significant contributors to forming the
coastal precipitation climatology, which for this area is found to be
distinctly different than for the rest of the region in terms of
precipitation concentration. 2012/08/08 - 11:14

Verification of ensemble forecasts of Mediterranean high-impact weather events against satellite observationsNatural Hazards and Earth System Science, 12, 2449-2462, 2012Author(s): J.-P. Chaboureau, O. Nuissier, and C. ClaudEnsemble forecasts at kilometre scale of two severe storms over the
Mediterranean region are verified against satellite observations. In
complement to assessing the forecasts against ground-based measurements,
brightness temperature (BT) images are computed from forecast fields and
directly compared to BTs observed from satellite. The so-called
model-to-satellite approach is very effective in identifying systematic
errors in the prediction of cloud cover for BTs in the infrared window and in
verifying the forecasted convective activity with BTs in the microwave range.
This approach is combined with the calculation of meteorological scores for
an objective evaluation of ensemble forecasts. The application of the
approach is shown in the context of two Mediterranean case studies, a
tropical-like storm and a heavy precipitating event. Assessment of cloud
cover and convective activity using satellite observations in the infrared
(10.8 μm) and microwave regions (183–191 GHz) provides results
consistent with other traditional methods using rainfall measurements. In
addition, for the tropical-like storm, differences among forecasts occur much
earlier in terms of cloud cover and deep convective activity than they do in
terms of deepening and track. Further, the underdispersion of the ensemble
forecasts of the two high-impact weather events is easily identified with
satellite diagnostics. This suggests that such an approach could be a useful
method for verifying ensemble forecasts, particularly in data-sparse regions. 2012/08/03 - 16:15

Uncertainty propagation for flood forecasting in the Alps: different views and impacts from MAP D-PHASENatural Hazards and Earth System Science, 12, 2439-2448, 2012Author(s): M. W. Rotach, M. Arpagaus, M. Dorninger, C. Hegg, A. Montani, and R. RanziD-PHASE was a Forecast Demonstration Project of the World Weather Research
Programme (WWRP) related to the Mesoscale Alpine Programme (MAP). Its goal
was to demonstrate the reliability and quality of operational forecasting of
orographically influenced (determined) precipitation in the Alps and its
consequences on the distribution of run-off characteristics. A special focus
was, of course, on heavy-precipitation events.

The D-PHASE Operations Period (DOP) ran from June to November~2007,
during which an end-to-end forecasting system was operated covering many
individual catchments in the Alps, with their water authorities, civil
protection organizations or other end users. The forecasting system's core
piece was a Visualization Platform where precipitation and flood warnings from some 30 atmospheric
and 7 hydrological models (both deterministic and probabilistic) and
corresponding model fields were displayed in uniform and comparable formats.
Also, meteograms, nowcasting information and end user communication was made
available to all the forecasters, users and end users. D-PHASE information
was assessed and used by some 50 different groups ranging from atmospheric
forecasters to civil protection authorities or water management bodies.

In the present contribution, D-PHASE is briefly presented along with its
outstanding scientific results and, in particular, the lessons learnt with
respect to uncertainty propagation. A focus is thereby on the transfer of
ensemble prediction information into the hydrological community and its use
with respect to other aspects of societal impact. Objective verification of
forecast quality is contrasted to subjective quality assessments during the
project (end user workshops, questionnaires) and some general conclusions
concerning forecast demonstration projects are drawn. 2012/08/03 - 16:15

A method to characterize the different extreme waves for islands exposed to various wave regimes: a case study devoted to Reunion IslandNatural Hazards and Earth System Science, 12, 2425-2437, 2012Author(s): S. Lecacheux, R. Pedreros, G. Le Cozannet, J. Thiébot, Y. De La Torre, and T. BulteauThis paper outlines a new approach devoted to the analysis of extreme waves
in presence of several wave regimes. It entails discriminating the
different wave regimes from offshore wave data using classification
algorithms, before conducting the extreme wave analysis for each regime
separately. The concept is applied to the pilot site of Reunion Island which
is affected by three main wave regimes: southern waves, trade-wind waves and
cyclonic waves. Several extreme wave scenarios are determined for each
regime, based on real historical cases (for cyclonic waves) and extreme
value analysis (for non-cyclonic waves). For each scenario, the nearshore
wave characteristics are modelled all around Reunion Island and the linear
theory equations are used to back calculate the equivalent deep-water wave
characteristics for each portion of the coast. The relative exposure of the
coastline to the extreme waves of each regime is determined by comparing the
equivalent deep-water wave characteristics.

This method provides a practical framework to perform an analysis of
extremes within a complex environment presenting several sources of extreme
waves. First, at a particular coastal location, it allows for
inter-comparison between various kinds of extreme waves that are generated
by different processes and that may occur at different periods of the year.
Then, it enables us to analyse the alongshore variability in wave exposition,
which is a good indicator of potential runup extreme values. For the case of
Reunion Island, cyclonic waves are dominant offshore around the island, with
equivalent deep-water wave heights up to 18 m for the northern part.
Nevertheless, due to nearshore wave refraction, southern waves may become as
energetic as cyclonic waves on the western part of the island and induce
similar impacts in terms of runup and submersion. This method can be easily
transposed to other case studies and can be adapted, depending on the data
availability. 2012/08/01 - 02:36

Grid based calibration of SWAT hydrological modelsNatural Hazards and Earth System Science, 12, 2411-2423, 2012Author(s): D. Gorgan, V. Bacu, D. Mihon, D. Rodila, K. Abbaspour, and E. RouholahnejadThe calibration and execution of large hydrological models, such as SWAT
(soil and water assessment tool), developed for large areas, high resolution,
and huge input data, need not only quite a long execution time but also high
computation resources. SWAT hydrological model supports studies and
predictions of the impact of land management practices on water, sediment,
and agricultural chemical yields in complex watersheds. The paper presents
the gSWAT application as a web practical solution for environmental
specialists to calibrate extensive hydrological models and to run scenarios,
by hiding the complex control of processes and heterogeneous resources across
the grid based high computation infrastructure. The paper highlights the
basic functionalities of the gSWAT platform, and the features of the
graphical user interface. The presentation is concerned with the development of
working sessions, interactive control of calibration, direct and basic
editing of parameters, process monitoring, and graphical and interactive
visualization of the results. The experiments performed on different SWAT
models and the obtained results argue the benefits brought by the grid
parallel and distributed environment as a solution for the processing
platform. All the instances of SWAT models used in the reported experiments
have been developed through the enviroGRIDS project, targeting the Black Sea
catchment area. 2012/08/01 - 02:36

Storm surge and wave simulations in the Gulf of Mexico using a consistent drag relation for atmospheric and storm surge modelsNatural Hazards and Earth System Science, 12, 2399-2410, 2012Author(s): D. Vatvani, N. C. Zweers, M. van Ormondt, A. J. Smale, H. de Vries, and V. K. MakinTo simulate winds and water levels, numerical weather prediction (NWP) and
storm surge models generally use the traditional bulk relation for wind
stress, which is characterized by a wind drag coefficient. A still commonly
used drag coefficient in those models, some of them were developed in the
past, is based on a relation, according to which the magnitude of the
coefficient is either constant or increases monotonically with increasing
surface wind speed (Bender, 2007; Kim et al., 2008; Kohno and Higaki, 2006). The NWP and surge
models are often tuned independently from each other in order to obtain good
results. Observations have indicated that the magnitude of the drag
coefficient levels off at a wind speed of about 30 m s−1, and then decreases
with further increase of the wind speed. Above a wind speed of approximately
30 m s−1, the stress above the air-sea interface starts to saturate. To
represent the reducing and levelling off of the drag coefficient, the
original Charnock drag formulation has been extended with a correction term.

In line with the above, the Delft3D storm surge model is tested using both
Charnock's and improved Makin's wind drag parameterization to evaluate the
improvements on the storm surge model results, with and without inclusion of
the wave effects. The effect of waves on storm surge is included by
simultaneously simulating waves with the SWAN model on identical model grids
in a coupled mode. However, the results presented here will focus on the
storm surge results that include the wave effects.

The runs were carried out in the Gulf of Mexico for Katrina and Ivan
hurricane events. The storm surge model was initially forced with H*wind
data (Powell et al., 2010) to test the effect of the Makin's wind drag
parameterization on the storm surge model separately. The computed wind,
water levels and waves are subsequently compared with observation data.
Based on the good results obtained, we conclude that, for a good reproduction
of the storm surges under hurricane conditions, Makin's new drag
parameterization is favourable above the traditional Charnock relation.
Furthermore, we are encouraged by these results to continue the studies and
establish the effect of improved Makin's wind drag parameterization in the
wave model.

The results from this study will be used to evaluate the relevance of
extending the present towards implementation of a similar wind drag
parameterization in the SWAN wave model, in line with our aim to apply a
consistent wind drag formulation throughout the entire storm surge modelling
approach. 2012/07/27 - 14:49

Seasonal forecast of French Mediterranean heavy precipitating events linked to weather regimesNatural Hazards and Earth System Science, 12, 2389-2398, 2012Author(s): J.-F. Guérémy, N. Laanaia, and J.-P. CéronSeasonal predictability of local precipitation is rather weak in the
mid-latitudes. This is the case when assessing the skill of the seasonal
forecast of Heavy Precipitating Event (HPE) extreme occurrence over the
French Mediterranean coast during the fall season. Tropics to extra-tropics
teleconnection patterns do appear when averaging analyzed fields over the
years characterised by a frequency of HPE occurrence in the upper
17% of the distribution. A methodology taking weather regime occurrence
into account as an intermediate step to forecast HPE extreme occurrence is
presented. For the period 1960 to 2001 and four different sets of seasonal
forecast, the Economical Value is doubled, compared to the score
obtained with the simulated local precipitation data, when using a linear
model (Linear Discriminant Analysis in this case) taking simulated 200 hPa
velocity potential–stream function regime occurrences as predictors.
Interestingly, larger scores are shown for this couple of fields
over a large-scale domain including the tropics than for the 500 hPa
geopotential height over an Euro–Atlantic domain, despite a tighter link of
the latter field to the local precipitation. 2012/07/25 - 20:16

Three-dimensional earthquake analysis of roller-compacted concrete damsNatural Hazards and Earth System Science, 12, 2369-2388, 2012Author(s): M. E. KartalGround motion effect on a roller-compacted concrete (RCC) dams in the
earthquake zone should be taken into account for the most critical
conditions. This study presents three-dimensional earthquake response of a
RCC dam considering geometrical non-linearity. Besides, material and
connection non-linearity are also taken into consideration in the
time-history analyses. Bilinear and multilinear kinematic hardening
material models are utilized in the materially non-linear analyses for
concrete and foundation rock respectively. The contraction joints inside the
dam blocks and dam–foundation–reservoir interaction are modeled by the
contact elements. The hydrostatic and hydrodynamic pressures of the
reservoir water are modeled with the fluid finite elements based on the
Lagrangian approach. The gravity and hydrostatic pressure effects are
employed as initial condition before the strong ground motion. In the
earthquake analyses, viscous dampers are defined in the finite element model
to represent infinite boundary conditions. According to numerical solutions,
horizontal displacements increase under hydrodynamic pressure. Besides,
those also increase in the materially non-linear analyses of the dam. In
addition, while the principle stress components by the hydrodynamic pressure
effect the reservoir water, those decrease in the materially non-linear
time-history analyses. 2012/07/24 - 22:59

Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic SeaNatural Hazards and Earth System Science, 12, 2347-2368, 2012Author(s): S. Torresan, A. Critto, J. Rizzi, and A. MarcominiSea level rise, changes in storms and wave climate as a consequence of
global climate change are expected to increase the size and magnitude of
flooded and eroding coastal areas, thus having profound impacts on
coastal communities and ecosystems. River deltas, beaches, estuaries and
lagoons are considered particularly vulnerable to the adverse effects of
climate change, which should be studied at the regional/local scale. This
paper presents a regional vulnerability assessment (RVA) methodology
developed to analyse site-specific spatial information on coastal
vulnerability to the envisaged effects of global climate change, and assist
coastal communities in operational coastal management and conservation. The
main aim of the RVA is to identify key vulnerable receptors (i.e. natural
and human ecosystems) in the considered region and localize vulnerable hot
spot areas, which could be considered as homogeneous geographic sites for the
definition of adaptation strategies. The application of the RVA methodology
is based on a heterogeneous subset of bio-geophysical and socio-economic
vulnerability indicators (e.g. coastal topography, geomorphology, presence
and distribution of vegetation cover, location of artificial protection),
which are a measure of the potential harm from a range of
climate-related impacts (e.g. sea level rise inundation, storm surge
flooding, coastal erosion). Based on a system of numerical weights and
scores, the RVA provides relative vulnerability maps that allow to
prioritize more vulnerable areas and targets of different climate-related
impacts in the examined region and to support the identification of suitable
areas for human settlements, infrastructures and economic activities,
providing a basis for coastal zoning and land use planning. The
implementation, performance and results of the methodology for the coastal
area of the North Adriatic Sea (Italy) are fully described in the paper. 2012/07/24 - 22:59

Uncorrected land-use planning highlighted by flooding: the Alba case study (Piedmont, Italy)Natural Hazards and Earth System Science, 12, 2329-2346, 2012Author(s): F. Luino, L. Turconi, C. Petrea, and G. NigrelliAlba is a town of over 30 000 inhabitants located along the Tanaro River
(Piedmont, northwestern Italy) and is famous for its wine and white
truffles. Many important industries and companies are based in Alba,
including the famous confectionery group Ferrero.

The town suffered considerably from a flood that occurred on 5–6 November 1994.
Forty-eight percent of the urban area was inundated, causing severe
damage and killing nine people. After the flood, the Alba area was analysed
in detail to determine the reasons for its vulnerability.

Information on serious floods in this area since 1800 was gathered from
official records, state technical office reports, unpublished documents in
the municipal archives, and articles published in local and national
newspapers. Maps, plans and aerial photographs (since 1954) were examined to
reconstruct Alba's urban development over the last two centuries and the
planform changes of the Tanaro River.

The results were compared with the effects of the November 1994 flood, which
was mapped from aerial photographs taken immediately after the flood, field
surveys and eyewitness reports.

The territory of Alba was subdivided into six categories: residential;
public service; industrial, commercial and hotels; sports areas, utilities
and standards (public gardens, parks, athletics grounds, private and public
sport clubs); aggregate plants and dumps; and agriculture and riverine
strip. The six categories were then grouped into three classes with
different flooding-vulnerability levels according to various parameters.
Using GIS, the three river corridors along the Tanaro identified by the
Autorità di Bacino del Fiume Po were overlaid on the three classes to
produce a final map of the risk areas.

This study shows that the historic floods and their dynamics have not been
duly considered in the land-use planning of Alba. The zones that were most
heavily damaged in the 1994 flood were those that were frequently affected in
the past and sites of more recent urbanisation. Despite recurrent severe
flooding of the Tanaro River and its tributaries, areas along the riverbed
and its paleochannels have been increasingly used for infrastructure and
building (e.g., roads, a municipal dump, a prison, natural aggregate plants,
a nomad camp), which has often interfered with the natural spread of the
floodwaters. Since the 1994 flood, many remedial projects have been completed
along the Tanaro and its tributaries, including levees, bank protection,
concrete walls and floodway channels. In spite of these costly projects, some
areas remain at high risk for flooding.

The method used, which considered historical data, river corridors
identified by hydraulic calculations, geomorphological aspects and land-use
planning, can indicate with good accuracy flood-prone areas and in
consequence to be an useful tool for the coherent planning of urban
expansion and the mitigation of flood risk. 2012/07/24 - 22:59

Active faults and historical earthquakes in the Messina Straits area (Ionian Sea)Natural Hazards and Earth System Science, 12, 2311-2328, 2012Author(s): A. Polonia, L. Torelli, L. Gasperini, and P. MussoniThe Calabrian Arc (CA) subduction complex is located at the toe of the
Eurasian Plate in the Ionian Sea, where sediments resting on the lower plate
have been scraped off and piled up in the accretionary wedge due to the
African/Eurasian plate convergence and back arc extension. The CA has been
struck repeatedly by destructive historical earthquakes, but knowledge of
active faults and source parameters is relatively poor, particularly for
seismogenic structures extending offshore. We analysed the fine structure of
major tectonic features likely to have been sources of past earthquakes:
(i) the NNW–SSE trending Malta STEP (Slab Transfer Edge
Propagator) fault system, representing a lateral tear of the subduction
system; (ii) the out-of-sequence thrusts (splay faults) at the rear of the
salt-bearing Messinian accretionary wedge; and (iii) the Messina Straits
fault system, part of the wide deformation zone separating the western and
eastern lobes of the accretionary wedge.

Our findings have implications for seismic hazard in southern Italy, as we
compile an inventory of first order active faults that may have produced
past seismic events such as the 1908, 1693 and 1169 earthquakes. These
faults are likely to be source regions for future large magnitude events as
they are long, deep and bound sectors of the margin characterized by
different deformation and coupling rates on the plate interface. 2012/07/24 - 22:59