Earthquake

Introduction

The ASEAN region is located at the intersection of three major tectonic plates namely Eurasian, Indo-Australian and the Pacific plates, and one minor plate, Philippine plate. This condition generates thousands of earthquake every year most of which are potentially destructive. In recent years, several big earthquakes occurred in some parts of ASEAN countries which caused considerable damage to buildings and other structures, landslides in mountainous regions, ground subsidence and ground rupture. These big earthquakes have also caused major fatalities. What makes an earthquake more devastating is the fact that it may generate tsunami with up to 10 meter high waves which add to the extent of the damage, especially in areas along the coast.

To monitor earthquake activities, and to help mitigate the effects of earthquake disasters, most countries in ASEAN have established their National Seismological Centres (NSCs). While NSCs in some countries are quite modern, others are still in the process of upgrading. Ideally each of the upgraded NSC should have a real time monitoring system and other facilities for rapid dissemination of earthquake information.

ASEAN member countries have been striving to improve the capabilities of NSCs in their respective countries to enable NSCs to conduct various activities and research programme addressing earthquake prediction and monitoring, proper land use planning, seismic hazard and risk assessment with different levels of techniques and degrees of depth. These are all aimed at mitigating the risks of earthquakes to mankind. These efforts are, however, hampered by common problems relating to trained personnel and adequate seismic facilities. One way of overcoming these problems is to establish a regional seismic information center where the services and facilities already available could be shared by all ASEAN member countries.


Whether occurring naturally or caused by man, earthquakes most often manifest themselves by a shaking of the ground. Most earthquakes are tectonic and occur when the frictional stress of gliding plate boundaries exceeds a certain value and causes a failure at a fault line, which results in a violent displacement of the Earth’s crust.

At this point, elastic strain energy is released and elastic waves are radiated, leading to an earthquake. Induced earthquakes may happen for a variety of reasons, including extraction of minerals from Earth and the collapse of large buildings.

An earthquake is a series of vibrations on the earth's surface caused by the generation of elastic (seismic) waves due to sudden rupture within the earth during release of accumulated strain energy.

Faulting may be considered as an immediate cause of an earthquake. Due to constant movement of plates, deformation is caused which results to generations of strain energy.

Indian plate is moving in north-north-east direction and colliding with Eurasian plate along the Himalayas.

One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects.

Earthquakes strike suddenly, violently, and without warning at any time of the day or night. If an earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage.

Although there are no guarantees of safety during an earthquake, identifying potential hazards ahead of time and advance planning can save lives and significantly reduce injuries and property damage.

The mission of the National Earthquake Information Center (NEIC) is to determine rapidly the location and size of all destructive earthquakes worldwide and to immediately disseminate this information to concerned national and international agencies, scientists, and the general public. The NEIC/WDC for Seismology compiles and maintains an extensive, global seismic database on earthquake parameters and their effects that serves as a solid foundation for basic and applied earth science research. Please visit the World Data Center web site to learn more about the WDC system.