by Dr. Afroz Ahmad Shah and Habibah Hanan Mat Yusoff
A magnitude 3.8 earthquake shook Baling (Kedah, Malaysia) at 8.26am, 20th August 2013. This raised some of the fundamental questions regarding the causes of earthquakes in Malaysia and primarily, our understanding and preparedness to handle earthquake disasters.
Malaysia is crisscrossed by a number of faults throughout the country, and most of these are not marked on the available geological maps. Since there is not much activity along these faults these are considered to be “inactive” structures. Not much scientific work has been done to understand the earthquake geology of these faults, which needs immediate attention. This is primarily because prior understanding has extensively demonstrated that active faults can also occur in regions formerly considered geologically stable. Therefore, it is significant to cognize the overall earthquake potential of all structures that can be mapped using the satellite images and field investigation.
The cause of earthquakes is well understood – an earthquake involves an “elastic rebound” of previously stored elastic stress. It is like a stretched rubber band, which if broken or cut, releases elastic energy stored in the rubber band during the stretching. Similarly, the earth’s crust can gradually store elastic stress that is suddenly released during an earthquake. This accumulation and release of stress and strain is now referred to as the “elastic rebound theory” of earthquakes, which is currently the best explanation available for the cause of the earthquakes.
To understand the cause of Baling earthquake, we have to first understand the earthquake parameters that were provided to us by the Meteorological Department of Malaysia. It was recorded that the magnitude of the earthquake was 3.8 and it occurred at an epicentral distance of 11 km to the south of Baling, however, the depth of the earthquake was not indicated. This is very important to know, because earthquakes occur at various depths and the deepest can go as deep as 700 km. Therefore, to understand this very event, its depth needs to be known. Once that is done, it is possible to determine if this has occurred on a shallow fault or on a deep portion of the fault or elsewhere. These procedures will eventually guide researchers to come up with a strategy and to understand the cause of such events, both of which are imperative for the country and its safety. This is done in a systematic pattern and the primary step is to extensively map all the active structures using the satellite images. This is followed by more vigorous field mapping, geophysical investigations and trenching on certain portions of the fault. Thus, with all the information gathered during these exercises, the earthquake potential along faults can be estimated, and this information is useful for building earthquake resistant structures.
Further, the current understanding of earthquake prediction is wisely crafted in a book “Predicting the Unpredictable: The Tumultuous Science of Earthquake Prediction” by U.S. Geological Survey geophysicist Susan E. Hough. The author emphasises that predicting earthquakes remains difficult for scientists due to various reasons that are discussed at length in the book. Therefore, with the current knowledge earth scientists cannot predict the exact timing and location of an earthquake; however, they can forecast these parameters and suggest various mitigation plans to reduce the damages and fatalities during an incoming event. Thus, humans must learn how to live with earthquakes. This can be achieved effectively through implementation of strict earthquake construction standards, careful geological evaluation of building sites, and public education. This is best exemplified by Japanese people, who have largely implemented these standards and therefore succeeded in building earthquake resistant structures and more importantly, a scientifically aware society. However, unlike Japan,a large number of people live in the developing world. Therefore, it is not easy to implement these standards, primarily because of the limited access to earthquake-related information, as well as general poverty, illiteracy and poor administration (Shah, 2013).
Bilham and V. Ghar (2013) also highlighted some of these concerns and discussed the earthquake risk in the developing world (e.g. India, Iran, Afghanistan, Bhutan, Bangladesh, Sri Lanka, and Myanmar). It is true that the developing world needs an enormous amount of work, which may take decades, to reach to the standards of Japan. However, the problem not only lies in the gathering of data, but more importantly so, the economic condition of a particular nation. A poor nation will always be more vulnerable to the damaging consequences of natural disasters (e.g. earthquakes, volcanoes, floods etc.), as shown by the degree of destruction caused by the Haiti earthquake of 2010 and the 2005 Kashmir earthquake. Both these earthquakes occurred in countries which are not only economically poor but also poorly governed. Therefore, it would be almost impractical to address the issues of natural disaster management without taking into account the economic and political facets of that country.
Equally challenging is to think that government can easily impose available construction standards on private structures in developing nations, because, this will again depend on the economic, political and administrative responsibilities of a nation. Only a responsible, honest and stable government will be able to implement suitable and effective procedures to counter natural disasters. Also, a scientifically literate and responsible society will help government to achieve such a goal and will also assist others to understand natural disasters. In particular, a significant portion of people in third world countries (such as India, Pakistan, Nepal, etc.) consider natural disasters as divine punishment, and therefore, do not interfere or question such calamities (Shah, 2013).
In conclusion, to achieve success in understanding earthquakes and to implement wise strategies, Malaysia needs to join international organisations and collaborate with them for a better future. This is because these groups are well-equipped with the latest developments in earthquake research, which will greatly benefit any country, including Malaysia. Therefore, strong international and national collaborations are required, wherein people from various disciplines can work together towards a common goal. Living with earthquakes is more to do with the overall stability of a particular nation,and that can only be achieved if we take it as a joint duty and work as an organised nation for a strong and stable future. Also, education in earth sciences could make a lot of difference in educating people about natural disasters, and more specifically, earthquakes. This can be achieved by organising various awareness programs and by introduction of earth sciences as a core field in the academic curricula (Shah, 2013).
- Hough, S., Predicting the Unpredictable: The Tumultuous Science of Earthquake Prediction, Princeton University Press, 2010, pp. 222.
- Bilham, R. and V. Gaur., Buildings as Weapons of Mass Destruction: Earthquake risk in South Asia, Science, 2013, 341, 618-619.
- Shah A. A., Kashmir Observer, 2013. 29 September.
About the Authors
Dr Afroz Ahmad Shah is a Senior Lecturer (Applied Geology) at the School of Engineering and Science, Curtin University, Sarawak. He obtained his PhD in 2010 (tectono-metamorphic evolution of Precambrian rocks) with Prof. Tim Bell in School of Earth & Environmental Sciences, James Cook University, Australia. He obtained an M.Tech. in engineering geosciences (2006) from IIT Kanpur India. He can be contacted at [email protected] Find out more about Dr. Afroz Ahmad Shah by visiting his Scientific Malaysian profile at http://www.scientificmalaysian.com/members/afrozshah/.
Habibah Hanan Mat Yusoff is a final year student in geology at University of Washington, Seattle, USA. She is currently working on an independent research about earthquakes and tectonics geomorphology in Southeast Asia focusing in Malaysia. Her collaborators are mainly Dr. Afroz Shah and other geoscience professors at University of Washington, Seattle. She will present her research around March 2014 in the Undergraduate Research Symposium at University of Washington, Seattle. She can be contacted at [email protected]. Find out more about Habibah by visiting her Scientific Malaysian profile at http://www.scientificmalaysian.com/members/habibah/.