Reducing Earthquake Hazards Research Articles

Evidence of structural segmentation of the Uttarakhand Himalaya and its implications for earthquake hazard

The earthquake hazard associated with the Main Himalayan Thrust (MHT) is a critical issue for India and its neighbouring countries in the north. We used data from a dense seismic network in Uttarakhand, India, to model the lateral variations in the depths of MHT (2–6% drop in Vs at 12–21 km depths), Moho (a sharp increase in Vs (by ~ 0.5–0.7 km/s) at 39–50 km depths) and lithosphere (a marked decrease in Vs(~ 1–3%) at 136–178 km depths), across the Himalayan collisional front. Our joint inversion of radial PRFs and group velocity dispersion data of Rayleigh waves detects three NNE trending transverse lithospheric blocks segmenting the lithosphere in Uttarakhand Himalaya, which spatially correlate well with the northward extension of the Delhi -Haridwar Indian basement ridge, an inferred tectonic boundary and great boundary fault, respectively. Our radial receiver function imaging detects highly deformed and segmented crustal and lithospheric structures associated with three mapped transverse lithospheric blocks, suggesting a reduction in rupture lengths of future earthquakes, thereby, reducing earthquake hazards in Uttarakhand.

The importance of surface ruptures and fault damage zones in earthquake hazard assessment: a review and new suggestions

Abstract Large earthquakes (M W > c. 6) generate surface ruptures and strong ground motions, resulting in extensive property damage and loss of lives. The earthquake damage and causality levels depend, for example, on the earthquake magnitude, seismic wave characteristics, the distance from the epicentre, the depth of earthquake and the foundation of related area . However, these factors cannot all be known for future earthquakes, because the exact times and locations of earthquakes cannot be predicted with the current technology. Thus, it is only possible to prepare for earthquakes by implementing anti-seismic design codes based on the local geological conditions. With accurate information about the locations of active faults or potential surface ruptures and deformation patterns, earthquake-prone areas could be avoided during site selection, especially for important facilities such as nuclear power plants and high-level radioactive waste disposal facilities. In this study, we investigated several factors for earthquake hazard estimation, focusing on the fault damage zones and respect distances. Fault damage zones around faults are mainly controlled by fault types, tip modes, exposed locations and slip senses along the fault. The characteristics of geological faults and earthquake ruptures show asymmetrical displacements and damage patterns, making it difficult to estimate respect distances and surface deformations. Therefore, both the respect distance and fault damage zone should be considered when identifying safe regions. This information will facilitate earthquake hazard assessment and appropriate site selection to reduce earthquake hazards in earthquake-prone areas.

Progress of the earthquake early warning system in Fujian, China

In this article, we systematically introduce the latest progress of the earthquake early warning (EEW) system in Fujian, China. We focus on the following key technologies and methods: continuous earthquake location and its error evaluation; magnitude estimation; reliability judgment of EEW system information; use of double-parameter principle in EEW system information release threshold; real-time estimation of seismic intensity and available time for target areas; seismic-monitoring network and data sharing platform; EEW system information release and receiving platform; software test platform; and test results statistical analysis. Based on strong ground motion data received in the mainshock of the Wenchuan earthquake, the EEW system developed by the above algorithm is simulated online, and the results show that the system can reduce earthquake hazards effectively. In addition, we analyzed four earthquake cases with magnitude greater than 5.5 processed by our EEW system since the online-testing that was started one year ago, and results indicate that our system can effectively reduce earthquake hazards and have high practical significance.

California Earthquakes: Science, Risks, and the Politics of Hazard Mitigation

“Politics” should be the lead word in the sub‐title of this engrossing study of the emergence and growth of the California and federal earthquake hazard reduction infrastructures. Beginning primarily with the 1906 San Francisco earthquake, scientists, engineers, and other professionals cooperated and clashed with state and federal officials, the business community, “ boosters,” and the general public to create programs, agencies, and commissions to support earthquake research and hazards mitigation. Moreover, they created a “regulatory‐state” apparatus that governs human behavior without sustained public support for its creation. The public readily accepts that earthquake research and mitigation are government responsibilities. The government employs or funds the scientists, engineers, emergency response personnel, safety officials, building inspectors, and others who are instrumental in reducing earthquake hazards. This book clearly illustrates how, and why all of this came to pass.

Priorities of earthquake research may be on shaky ground

Congressional checks on the effectiveness and direction of earthquake research and development in the United States may mean securing grants for basic research will be tougher in the future, some observers say, that is, unless scientists can do a better job of getting their message out.The January Northridge earthquake has prompted awareness, as well as criticism of current federal efforts to reduce earthquake hazards. In addition to a study launched in February by the White House, the Office of Technology Assessment recently gave the thumbs up for a study, requested by the House Science, Space and Technology Committee, to evaluate federal efforts in reducing earthquake damage—how best to set research and development priorities and to ensure practical use of research findings.

AGU develops earthquake curriculum

AGU, in cooperation with the Federal Emergency Management Agency (FEMA), announces the production of a new curriculum package for grades 7–12 on the engineering and geophysical aspects of earthquakes.According to Frank Ireton, AGU's precollege education manager, “Both AGU and FEMA are working to promote the understanding of earthquake processes and their impact on the built environment. We are designing a program that involves students in learning how science, mathematics, and social studies concepts can be applied to reduce earthquake hazards.”

Coalition forms to support NEHRP

A group of professional associations, including the Seismological Society of America and the Earthquake Engineering Research Institute, has formed a coalition to support the National Earthquake Hazards Reduction Program (NEHRP). Meeting in met on February 20, the group plans to actively support the research necessary to mitigate earthquake losses and to seek continued federal funding of the program.NEHRP was established by President Carter following the Earthquake Hazards Reduction Act of 1977. Funding was originally authorized for 3 years and has been reauthorized by Congress each year. The program is funded through four federal agencies—the U.S. Geological Survey, National Science Foundation, Federal Emergency Management Agency, and the National Institute of Stan dards and Technology. Its purpose is to address the nation's earthquake threat by reducing earthquake hazards.

California at Risk: Where Do We Go from Here?

In 1986, the state of California embarked on a comprehensive earthquake hazard reduction program described in California at Risk: Reducing Earthquake Hazards 1987-1992. This Program identifies hazard reduction efforts for existing development, emergency response, future development, recovery planning, education, and research. The goal is to reduce the state's earthquake hazards significantly by the year 2000. This paper reviews the development of the Program, the state's progress toward hazard reduction, seismic safety legislation and refinements in the Program's second five years.

Reducing Earthquake Hazards - Lessons Learned from Earthquakes

Reducing Earthquake Hazards - Lessons Learned from Earthquakes

The use of geologic and seismologic information to reduce earthquake Hazards in California

Five examples illustrate how geologic and seismologic information can be used to reduce the effects of earthquakes Included are procedures for anticipating damage to critical facilities, preparing, adopting, or implementing seismic safety studies, plans, and programs, retrofitting highway bridges, regulating development in areas subject to fault-rupture, and strengthening or removing unreinforced masonry buildings. The collective effect of these procedures is to improve the public safety, health, and welfare of individuals and their communities.

Joint Commerce‐HUD Earthquake Research Project announced

A research project to reduce earthquake hazards through improved land use and building codes and to provide information for improving insurance programs will be undertaken by the Department of Commerce and the Department of Housing and Urban Development.To start the project, HUD will provide $155,000 to NOAA for the eighteen‐month study. NOAA conducts a broad program of studies related to earthquake hazard reduction and has developed strong working ties with the Earthquake Engineering Research Institute. EERI, a non‐profit corporation established in the public interest, consists of experts in all aspects of earthquake engineering. A significant aspect of the agreement is that NOAA will be able to call upon the capability in earthquake engineering of the EERI. Also participating will be the National Bureau of Standards and the U.S. Geological Survey.

U.S. Geological Survey research on the tectonics of the San Andreas Fault System, California: Introduction

The U.S. Geological Survey's National Center for Earthquake Research (NCER) was established in Menlo Park, California, by the Secretary of the Interior Stewart L. Udall in October 1965 for the purpose of organizing a broad, interdisciplinary program of earthquake research. The goal of NCER is to reduce earthquake hazards through improved knowledge of the fundamental nature and causes of earthquakes that may eventually lead to earthquake prediction. In general, the program of NCER follows the recommendations of the Ad Hoc Panel on Earthquake Prediction of the Office of Science and Technology and the Ad Hoc Interagency Working Group for Earthquake Research of the Federal Council for Science and Technology. Although the NCER program is national in scope, initial emphasis has been placed on the San Andreas fault system, California. Research on the tectonics of the San Andreas fault system includes geologic studies, seismological studies, and strain studies. These and related studies in experimental geology and engineering geology are coordinated by the NCER Executive Committee.