On some recent achievements of earthquake simulation

AbstractThis paper presents some recent achievements of earthquake simulation, which is divided into the seismic wave propagation simulation and the seismic structure response simulation. These achievements are based on rigorous mathematical treatment of continuum mechanics problems, and numerical algorithms of solving the problems are developed. A multi-scale analysis method is developed for the seismic wave propagation simulation; numerical dispersion is reduced by introducing a new discretization scheme. A smart treatment of crack initiation and propagation is developed for the seismic structure response simulation, so that a numerical experiment is made for failure processes by using numerous samples of one structure

Heritage and Resilience: Issues and Opportunities for Reducing Disaster Risks

This paper examines the unique role of cultural heritage in disaster risk reduction. Itintroduces various approaches to protect heritage from irreplaceable loss and considers ways to draw upon heritage as an asset in building the resilience of communities and nations to disasters. The paper proposes ways forward and builds on the current momentum provided by the Hyogo Framework for Action 2005-2015: Building the Resilience of Nations and Communities to Disasters” (HFA) and the advancement of a post-2015 framework for disaster risk reduction (HFA2) and the post-2015 development agenda. Cultural heritage is often associated with grandiose monuments and iconic archaeological sites that can hold us in awe of their beauty, history and sheer scale. However, the understanding of cultural heritage has undergone a marked shift during the last few decades in terms of what it is, why it is important, why it is at risk and what can be done to protect it. Cultural heritage today encompasses a broader array of places such as historic cities, living cultural landscapes, gardens or sacred forests and mountains, technological or industrial achievements in the recent past and even sites associated with painful memories and war. Collections of movable and immoveable items within sites, museums, historic properties and archives have also increased significantly in scope, testifying not only to the lifestyles of royalty and the achievements of great artists, but also to the everyday lives of ordinary people. At the same time intangibles such as knowledge, beliefs and value systems are fundamental aspects of heritage that have a powerful influence on people’s daily choices and behaviors. Heritage is at risk due to disasters, conflict, climate change and a host of other factors.At the same time, cultural heritage is increasingly recognized as a driver of resilience that can support efforts to reduce disaster risks more broadly. Recent years have seen greater emphasis and commitment to protecting heritage and leveraging it for resilience;but initiatives, such as the few examples that are presented here, need to be encouraged and brought more fully into the mainstream of both disaster risk reduction and heritage management. These are issues that can be productively addressed in a post-2015 framework for disaster risk reduction and, likewise, in the post-2015 development agenda

Spartan Daily, September 4, 2014

Volume 143, Issue 4https://scholarworks.sjsu.edu/spartandaily/1503/thumbnail.jp

Recent Milestones in Unraveling the Full-Field Structure of Dynamic Shear Cracks and Fault Ruptures in Real-Time: From Photoelasticity to Ultrahigh-Speed Digital Image Correlation

The last few decades have seen great achievements in dynamic fracture mechanics. Yet, it was not possible to experimentally quantify the full-field behavior of dynamic fractures, until very recently. Here, we review our recent work on the full-field quantification of the temporal evolution of dynamic shear ruptures. Our newly developed approach based on digital image correlation combined with ultrahigh-speed photography has revolutionized the capabilities of measuring highly transient phenomena and enabled addressing key ques- tions of rupture dynamics. Recent milestones include the visualization of the complete displacement, particle velocity, strain, stress and strain rate fields near growing ruptures, capturing the evolution of dynamic friction during individual rupture growth, and the detailed study of rupture speed limits. For example, dynamic friction has been the big- gest unknown controlling how frictional ruptures develop but it has been impossible, until now, to measure dynamic friction during spontaneous rupture propagation and to understand its dependence on other quantities. Our recent measurements allow, by simul- taneously tracking tractions and sliding speeds on the rupturing interface, to disentangle its complex dependence on the slip, slip velocity, and on their history. In another application, we have uncovered new phenomena that could not be detected with previous methods, such as the formation of pressure shock fronts associated with “supersonic” propagation of shear ruptures in viscoelastic materials where the wave speeds are shown to depend strongly on the strain rate

"Last-Mile" preparation for a potential disaster

Extreme natural events, like e.g. tsunamis or earthquakes, regularly lead to catastrophes with dramatic consequences. In recent years natural disasters caused hundreds of thousands of deaths, destruction of infrastructure, disruption of economic activity and loss of billions of dollars worth of property and thus revealed considerable deficits hindering their effective management: Needs for stakeholders, decision-makers as well as for persons concerned include systematic risk identification and evaluation, a way to assess countermeasures, awareness raising and decision support systems to be employed before, during and after crisis situations. The overall goal of this study focuses on interdisciplinary integration of various scientific disciplines to contribute to a tsunami early warning information system. In comparison to most studies our focus is on high-end geometric and thematic analysis to meet the requirements of small-scale, heterogeneous and complex coastal urban systems. Data, methods and results from engineering, remote sensing and social sciences are interlinked and provide comprehensive information for disaster risk assessment, management and reduction. In detail, we combine inundation modeling, urban morphology analysis, population assessment, socio-economic analysis of the population and evacuation modeling. The interdisciplinary results eventually lead to recommendations for mitigation strategies in the fields of spatial planning or coping capacity