Hydro-mechanical Analysis of Rainfall-Induced Landslides

Download Hydro-mechanical Analysis of Rainfall-Induced Landslides PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 9811507619
Total Pages : 245 pages
Book Rating : 4.8/5 (115 download)

DOWNLOAD NOW!


Book Synopsis Hydro-mechanical Analysis of Rainfall-Induced Landslides by : Lizhou Wu

Download or read book Hydro-mechanical Analysis of Rainfall-Induced Landslides written by Lizhou Wu and published by Springer Nature. This book was released on 2020-01-14 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most landslides are triggered by rainfall. In previous studies, slope stability is often evaluated based on the infiltration analysis. Hydro-mechanical coupling is significant to rainfall-caused landslide evolution. This book covers theoretical models of unsaturated infiltration, and provides hydro-mechanical models for rainfall-induced landslides. The influences of rainfall patterns, boundary conditions, layered structures, and SWCC hysteresis on the coupled unsaturated infiltration and deformation are discussed. Laboratory testing of rainfall-induced landslides is performed to study the developing process of landslide upon rainfall infiltration. The results provide a better understanding of rainfall-induced landslides.

Rainfall-triggered Landslides: Conditions, Prediction, and Warning

Download Rainfall-triggered Landslides: Conditions, Prediction, and Warning PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

DOWNLOAD NOW!


Book Synopsis Rainfall-triggered Landslides: Conditions, Prediction, and Warning by : Lisa Victoria Luna

Download or read book Rainfall-triggered Landslides: Conditions, Prediction, and Warning written by Lisa Victoria Luna and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Rainfall-triggered Landslides

Download Rainfall-triggered Landslides PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (14 download)

DOWNLOAD NOW!


Book Synopsis Rainfall-triggered Landslides by : Lisa Luna

Download or read book Rainfall-triggered Landslides written by Lisa Luna and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rainfall-triggered landslides are a globally occurring hazard that cause several thousand fatalities per year on average and lead to economic damages by destroying buildings and infrastructure and blocking transportation networks. For people living and governing in susceptible areas, knowing not only where, but also when landslides are most probable is key to inform strategies to reduce risk, requiring reliable assessments of weather-related landslide hazard and adequate warning. Taking proper action during high hazard periods, such as moving to higher levels of houses, closing roads and rail networks, and evacuating neighborhoods, can save lives. Nevertheless, many regions of the world with high landslide risk currently lack dedicated, operational landslide early warning systems. The mounting availability of temporal landslide inventory data in some regions has increasingly enabled data-driven approaches to estimate landslide hazard on the basis of rainfall conditions. In other areas, however, such data remains scarce, calling ...

Influence of Rainfall and Ancient Landslide Deposits on Recent Landslides (1950-71) in Urban Areas of Contra Costa County, California

Download Influence of Rainfall and Ancient Landslide Deposits on Recent Landslides (1950-71) in Urban Areas of Contra Costa County, California PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 28 pages
Book Rating : 4.3/5 (121 download)

DOWNLOAD NOW!


Book Synopsis Influence of Rainfall and Ancient Landslide Deposits on Recent Landslides (1950-71) in Urban Areas of Contra Costa County, California by : Tor Helge Nilsen

Download or read book Influence of Rainfall and Ancient Landslide Deposits on Recent Landslides (1950-71) in Urban Areas of Contra Costa County, California written by Tor Helge Nilsen and published by . This book was released on 1975 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Rainfall-Induced Landslides Hazard

Download Rainfall-Induced Landslides Hazard PDF Online Free

Author :
Publisher :
ISBN 13 : 9783036521770
Total Pages : 128 pages
Book Rating : 4.5/5 (217 download)

DOWNLOAD NOW!


Book Synopsis Rainfall-Induced Landslides Hazard by : Clemente Irigaray

Download or read book Rainfall-Induced Landslides Hazard written by Clemente Irigaray and published by . This book was released on 2021-11 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes five articles and a technical note recently published in the Special Issue "Rainfall-Induced Landslides Hazard" from the journal Hydrology. Its main objective is to describe the latest developments and applications of the use of new numerical and analytical methods to improve our understanding of rainfall-induced landslide models and other aspects of landslide-hazard assessment. In the first article, based on the estimation of rainfall thresholds and their return periods in a sector of southern Spain, a linear equation for the rainfall duration threshold and a power-law curve for the intensity-duration pair were determined. The second and fourth articles present two case studies in Italy on the assessment of landslide susceptibility. One of them uses the Weight of Evidence method and takes into account parameters such as geology, activity, land use, average annual precipitation and extreme precipitation events, and the other one compares Forward Conditional Analysis and Forward Logistic Regression methods. The next work aims to generate and compare the basic information on rainfall events triggering landslides in two areas with different climate and geological settings (southern Ecuador and southern Spain). In addition, this paper gives preliminary insights into the correlation between these rainfall events and major climate cycles affecting each of these study areas. The last article focuses on the estimation of evapotranspiration using remote sensing and the Surface Energy Balance Algorithm for Land in western Iran. Finally, the technical note presents a procedure to determine and validate the probabilities for landslide occurrence by using different precipitation parameters (rainfall intensity, rainfall duration and event rainfall) in Bhutan.

Rainfall Triggered Landslides and Debris Flow and Possible Warning

Download Rainfall Triggered Landslides and Debris Flow and Possible Warning PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 52 pages
Book Rating : 4.:/5 (643 download)

DOWNLOAD NOW!


Book Synopsis Rainfall Triggered Landslides and Debris Flow and Possible Warning by :

Download or read book Rainfall Triggered Landslides and Debris Flow and Possible Warning written by and published by . This book was released on 2000 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Abrupt Impacts of Climate Change

Download Abrupt Impacts of Climate Change PDF Online Free

Author :
Publisher : National Academies Press
ISBN 13 : 0309287766
Total Pages : 281 pages
Book Rating : 4.3/5 (92 download)

DOWNLOAD NOW!


Book Synopsis Abrupt Impacts of Climate Change by : National Research Council

Download or read book Abrupt Impacts of Climate Change written by National Research Council and published by National Academies Press. This book was released on 2013-12-31 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate is changing, forced out of the range of the past million years by levels of carbon dioxide and other greenhouse gases not seen in the Earth's atmosphere for a very, very long time. Lacking action by the world's nations, it is clear that the planet will be warmer, sea level will rise, and patterns of rainfall will change. But the future is also partly uncertain-there is considerable uncertainty about how we will arrive at that different climate. Will the changes be gradual, allowing natural systems and societal infrastructure to adjust in a timely fashion? Or will some of the changes be more abrupt, crossing some threshold or "tipping point" to change so fast that the time between when a problem is recognized and when action is required shrinks to the point where orderly adaptation is not possible? Abrupt Impacts of Climate Change is an updated look at the issue of abrupt climate change and its potential impacts. This study differs from previous treatments of abrupt changes by focusing on abrupt climate changes and also abrupt climate impacts that have the potential to severely affect the physical climate system, natural systems, or human systems, often affecting multiple interconnected areas of concern. The primary timescale of concern is years to decades. A key characteristic of these changes is that they can come faster than expected, planned, or budgeted for, forcing more reactive, rather than proactive, modes of behavior. Abrupt Impacts of Climate Change summarizes the state of our knowledge about potential abrupt changes and abrupt climate impacts and categorizes changes that are already occurring, have a high probability of occurrence, or are unlikely to occur. Because of the substantial risks to society and nature posed by abrupt changes, this report recommends the development of an Abrupt Change Early Warning System that would allow for the prediction and possible mitigation of such changes before their societal impacts are severe. Identifying key vulnerabilities can help guide efforts to increase resiliency and avoid large damages from abrupt change in the climate system, or in abrupt impacts of gradual changes in the climate system, and facilitate more informed decisions on the proper balance between mitigation and adaptation. Although there is still much to learn about abrupt climate change and abrupt climate impacts, to willfully ignore the threat of abrupt change could lead to more costs, loss of life, suffering, and environmental degradation. Abrupt Impacts of Climate Change makes the case that the time is here to be serious about the threat of tipping points so as to better anticipate and prepare ourselves for the inevitable surprises.

Map Showing Susceptibility to Rainfall-triggered Landslides in the Municipality of Ponce, Puerto Rico

Download Map Showing Susceptibility to Rainfall-triggered Landslides in the Municipality of Ponce, Puerto Rico PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 22 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis Map Showing Susceptibility to Rainfall-triggered Landslides in the Municipality of Ponce, Puerto Rico by : Geological Survey (U.S.)

Download or read book Map Showing Susceptibility to Rainfall-triggered Landslides in the Municipality of Ponce, Puerto Rico written by Geological Survey (U.S.) and published by . This book was released on 2004 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Extreme rainfall induced landslides

Download Extreme rainfall induced landslides PDF Online Free

Author :
Publisher : Oficina de Textos
ISBN 13 : 8579751446
Total Pages : 413 pages
Book Rating : 4.5/5 (797 download)

DOWNLOAD NOW!


Book Synopsis Extreme rainfall induced landslides by : Willy Alvarenga Lacerda

Download or read book Extreme rainfall induced landslides written by Willy Alvarenga Lacerda and published by Oficina de Textos. This book was released on with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book assembles most of the works presented at the International Workshop on Extreme Rainfall Induced Landslides, held in Rio de Janeiro 11-15 February 2012, in response to the landslide disaster which occurred in the Serrana Region of Rio de Janeiro one year before, and also other disasters in the states of Santa Catarina, São Paulo, Pernambuco, Alagoas, and Minas Gerais. The workshop brought together great landslide experts from all around the world, and the outcome was a Final Report sent to competent governmental Brazilian authorities. The presentations, discussions and lessons learned highlighted the urgency of governmental actions to incentivize scientific and technological researches, aiming to accelerate the methodological development in order to avoid, reduce and mitigate the hazardous consequences of these natural disasters.

Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning

Download Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning PDF Online Free

Author :
Publisher : MDPI
ISBN 13 : 3036509305
Total Pages : 222 pages
Book Rating : 4.0/5 (365 download)

DOWNLOAD NOW!


Book Synopsis Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning by : Samuele Segoni

Download or read book Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning written by Samuele Segoni and published by MDPI. This book was released on 2021-06-22 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Landslides are destructive processes causing casualties and damage worldwide. The majority of the landslides are triggered by intense and/or prolonged rainfall. Therefore, the prediction of the occurrence of rainfall-induced landslides is an important scientific and social issue. To mitigate the risk posed by rainfall-induced landslides, landslide early warning systems (LEWS) can be built and applied at different scales as effective non-structural mitigation measures. Usually, the core of a LEWS is constituted of a mathematical model that predicts landslide occurrence in the monitored areas. In recent decades, rainfall thresholds have become a widespread and well established technique for the prediction of rainfall-induced landslides, and for the setting up of prototype or operational LEWS. A rainfall threshold expresses, with a mathematic law, the rainfall amount that, when reached or exceeded, is likely to trigger one or more landslides. Rainfall thresholds can be defined with relatively few parameters and are very straightforward to operate, because their application within LEWS is usually based only on the comparison of monitored and/or forecasted rainfall. This Special Issue collects contributions on the recent research advances or well-documented applications of rainfall thresholds, as well as other innovative methods for landslide prediction and early warning. Contributions regarding the description of a LEWS or single components of LEWS (e.g., monitoring approaches, forecasting models, communication strategies, and emergency management) are also welcome. We encourage, in particular, the submission of contributions concerning the definition and validation of rainfall thresholds, and their operative implementation in LEWS. Other approaches for the forecasting of landslides are also of interest, such as physically based modelling, hazard mapping, and the monitoring of hydrologic and geotechnical indicators, especially when described in the framework of an operational or prototype early warning system.

Advancing Culture of Living with Landslides

Download Advancing Culture of Living with Landslides PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 3319534858
Total Pages : 690 pages
Book Rating : 4.3/5 (195 download)

DOWNLOAD NOW!


Book Synopsis Advancing Culture of Living with Landslides by : Matjaž Mikoš

Download or read book Advancing Culture of Living with Landslides written by Matjaž Mikoš and published by Springer. This book was released on 2017-05-20 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains peer-reviewed papers from the Fourth World Landslide Forum organized by the International Consortium on Landslides (ICL), the Global Promotion Committee of the International Programme on Landslides (IPL), University of Ljubljana (UL) and Geological Survey of Slovenia in Ljubljana, Slovenia from May 29 to June 2, 2017. The complete collection of papers from the Forum is published in five full-color volumes. This fourth volume contains the following: • Earthquake-Induced Landslides • Rainfall-Induced Landslides • Rapid Landslides: Debris Flows, Mudflows, Rapid Debris-Slides • Landslides in Rocks and Complex Landslides: Rock Topples, Rock Falls, Rock Slides,Complex Landslides • Landslides and Other Natural Hazards: Floods, Droughts, Wildfires, Tsunamis, Volcanoes Prof. Matjaž Mikoš is the Forum Chair of the Fourth World Landslide Forum. He is the Vice President of International Consortium on Landslides and President of the Slovenian NationalPlatform for Disaster Risk Reduction. Prof. Nicola Casagli is Founding member of the International Consortium on Landslides(ICL), professor at the University of Florence and founder of the UNESCO Chair on geohydrological hazards at the same University. Prof. Yueping Yin is the President of the International Consortium on Landslides and the Chairman of the Committee of Geo-Hazards Prevention of China, and the Chief Geologist of Geo-Hazard Emergency Technology, Ministry of Land and Resources, P.R. China”. Prof. Kyoji Sassa is the Founding President of the International Consortium on Landslides(ICL). He is Executive Director of ICL and the Editor-in-Chief of International Journal“Landslides” since its foundation in 2004. IPL (International Programme on Landslides) is a programme of the ICL. The programme is managed by the IPL Global Promotion Committee including ICL and ICL supportingorganizations, UNESCO, WMO, FAO, UNISDR, UNU, ICSU, WFEO, IUGS and IUGG. TheIPL contributes to the United Nations International Strategy for Disaster Reduction and the ISDR-ICL Sendai Partnerships 2015-2025.

Impact of Climate Change, Land Use and Land Cover, and Socio-economic Dynamics on Landslides

Download Impact of Climate Change, Land Use and Land Cover, and Socio-economic Dynamics on Landslides PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 9811673144
Total Pages : 493 pages
Book Rating : 4.8/5 (116 download)

DOWNLOAD NOW!


Book Synopsis Impact of Climate Change, Land Use and Land Cover, and Socio-economic Dynamics on Landslides by : Raju Sarkar

Download or read book Impact of Climate Change, Land Use and Land Cover, and Socio-economic Dynamics on Landslides written by Raju Sarkar and published by Springer Nature. This book was released on 2022-01-03 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the impact of climate change, land use and land cover, and socio-economic dynamics on landslides in Asian countries. Scholars recently have brought about a shift in their focus regarding triggering factors for landslides, from rainfall or earthquake to claiming rapid urbanization, extreme population pressure, improper land use planning, illegal hill cutting for settlements and indiscriminate deforestation. This suggests that the occurrence or probabilities of landslides are shaped by both climate-related and non-climate-related anthropogenic factors. Among these issues, land use and land cover change or improper land use planning is one of the key factors. Further climate change shapes the rainfall pattern and intensity in different parts of the world, and consequently rainfall-triggered landslides have increased. These changes cause socio-economic changes. Conversely, socio-economic and lifestyle changes enhance inappropriate land use and climate change. All these changes in land use, climate and socio-economic aspects are dynamics in nature and shape landslide risks in Asian countries, where they are given serious attention by governments, disaster management professionals, researchers and academicians. This book comprises 21 chapters divided into three major sections highlighting the effect of climate change on landslide incidence with the influence on vegetation and socio-economic aspects. The sections address how climate change and extreme events have triggered landslides. The advances in geospatial techniques with the focus on land use and land cover change along with the effect on socio-economic aspects are also explored.

Multi-Hazard Early Warning and Disaster Risks

Download Multi-Hazard Early Warning and Disaster Risks PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 3030730034
Total Pages : 914 pages
Book Rating : 4.0/5 (37 download)

DOWNLOAD NOW!


Book Synopsis Multi-Hazard Early Warning and Disaster Risks by : Dilanthi Amaratunga

Download or read book Multi-Hazard Early Warning and Disaster Risks written by Dilanthi Amaratunga and published by Springer Nature. This book was released on 2021-09-11 with total page 914 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a collection of papers under the theme of multi-hazard early warning and disaster risks. These were selected from the presentations made at the International Symposium on Tsunami and Multi-Hazard Risks, Early Warning and Community Awareness in supporting implementation of the Sendai Framework for Disaster Risk Reduction 2015-2030. This conference aimed to recognize achievements and to highlight work that still needs to be carried out. The conference promoted collaboration among academia, research institutions and disaster management offices, and further encouraged multidisciplinary and multi-sectoral interaction This International Symposium on Multi-Hazard Early Warning and Disaster Risk Reduction provided an important opportunity to reflect upon our progress to date in tackling disaster risk, but also to consider some of the challenges and opportunities that lay ahead of us. A particular focus of this event wasMulti-Hazard Early Warning. During the negotiations for the Sendai Framework, countries and partners highlighted the need to: 1. Continue to invest in, develop, maintain and strengthen people-centred, end-to-end early warning systems; 2. Promote the application of simple and low cost early warning equipment and facilities; 3. Broaden the dissemination channels for early warning information to facilitate early action. Countries also called for the further development of and investment in effective, nationally compatible, regional multi-hazard early warning mechanisms. To address these needs, global Target (g) of the Sendai Framework was adopted, namely to “substantially increase the availability of and access to multi-hazard early warning systems and disaster risk information and assessments to the people by 2030”. As illustrated by recent events in Indonesia, it is also vital to address the challenge of cascading hazards that pose a tsunami risk, and the importance of linking tsunami early warning to a multi-hazard environment. However, moving towards a multi-hazard environment is complex and poses many challenges but can bring significant benefits in terms of efficiencies and also in recognising the links between hazards, such as cascading threats. We very much hope that this book will provide an important platform to address these and other challenges in addressing disaster risk, as well as supporting implementation of the Sendai Framework for Disaster Risk Reduction

The Occurrence and Behavior of Rainfall-triggered Landslides in Coastal British Columbia

Download The Occurrence and Behavior of Rainfall-triggered Landslides in Coastal British Columbia PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 176 pages
Book Rating : 4.:/5 (613 download)

DOWNLOAD NOW!


Book Synopsis The Occurrence and Behavior of Rainfall-triggered Landslides in Coastal British Columbia by : Richard Hamilton Guthrie

Download or read book The Occurrence and Behavior of Rainfall-triggered Landslides in Coastal British Columbia written by Richard Hamilton Guthrie and published by . This book was released on 2009 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis seeks to analyze the occurrence and behavior of rainfall-triggered landslides in coastal British Columbia. In particular, it focuses on the analysis of landslide temporal and spatial distributions occurrence and their magnitudes, and considers the major factors that influence regional landslide behavior. Implicit in the research is the understanding that the landscape of coastal BC is managed, and that landslides, in addition to occurring naturally may be caused by, and certainly impact, resources that are important to humankind. Underlying each chapter is the rationale that by better understanding the causes of, and controls on landslide occurrence and magnitude, we can reduce the impacts and lower the associated risk.

Smoothing Methods in Statistics

Download Smoothing Methods in Statistics PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1461240263
Total Pages : 349 pages
Book Rating : 4.4/5 (612 download)

DOWNLOAD NOW!


Book Synopsis Smoothing Methods in Statistics by : Jeffrey S. Simonoff

Download or read book Smoothing Methods in Statistics written by Jeffrey S. Simonoff and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focussing on applications, this book covers a very broad range, including simple and complex univariate and multivariate density estimation, nonparametric regression estimation, categorical data smoothing, and applications of smoothing to other areas of statistics. It will thus be of particular interest to data analysts, as arguments generally proceed from actual data rather than statistical theory, while the "Background Material" sections will interest statisticians studying the field. Over 750 references allow researchers to find the original sources for more details, and the "Computational Issues" sections provide sources for statistical software that use the methods discussed. Each chapter includes exercises with a heavily computational focus based upon the data sets used in the book, making it equally suitable as a textbook for a course in smoothing.

Satellite Rainfall Applications for Surface Hydrology

Download Satellite Rainfall Applications for Surface Hydrology PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 904812915X
Total Pages : 327 pages
Book Rating : 4.0/5 (481 download)

DOWNLOAD NOW!


Book Synopsis Satellite Rainfall Applications for Surface Hydrology by : Mekonnen Gebremichael

Download or read book Satellite Rainfall Applications for Surface Hydrology written by Mekonnen Gebremichael and published by Springer Science & Business Media. This book was released on 2009-12-02 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions from a panel of researchers from a wide range of fields, the chapters of this book focus on evaluating the potential, utility and application of high resolution satellite precipitation products in relation to surface hydrology.

Hillslope Hydrology and Stability

Download Hillslope Hydrology and Stability PDF Online Free

Author :
Publisher : Cambridge University Press
ISBN 13 : 1139619853
Total Pages : 463 pages
Book Rating : 4.1/5 (396 download)

DOWNLOAD NOW!


Book Synopsis Hillslope Hydrology and Stability by : Ning Lu

Download or read book Hillslope Hydrology and Stability written by Ning Lu and published by Cambridge University Press. This book was released on 2013-01-17 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Landslides are caused by a failure of the mechanical balance within hillslopes. This balance is governed by two coupled physical processes: hydrological or subsurface flow and stress. The stabilizing strength of hillslope materials depends on effective stress, which is diminished by rainfall. This book presents a cutting-edge quantitative approach to understanding hydro-mechanical processes across variably saturated hillslope environments and to the study and prediction of rainfall-induced landslides. Topics covered include historic synthesis of hillslope geomorphology and hydrology, total and effective stress distributions, critical reviews of shear strength of hillslope materials and different bases for stability analysis. Exercises and homework problems are provided for students to engage with the theory in practice. This is an invaluable resource for graduate students and researchers in hydrology, geomorphology, engineering geology, geotechnical engineering and geomechanics and for professionals in the fields of civil and environmental engineering and natural hazard analysis.