Myanmar has frequent geological disasters including earthquakes, tsunamis, landslides, and subsidences in karst area. Myanmar indeed is an earthquake-prone area as it lies in one of the two main earthquake belts of the world, known as the Alpide Belt that extends from the Mediterranean through Turkey, Iran, Afghanistan the Himalayas and Myanmar to finally Indonesia. Therefore, Myanmar is vulnerable to hazards from moderate and large magnitude earthquakes, including tsunami hazards along its long coastal areas.
The seismotectonics of the region indicate that earthquakes in Myanmar mostly originates along an active subduction zone (Andaman Megathrust Zone) in the West and along a large active transform fault zone (Sagaing Fault Zone) in the middle part of the country. Local historic records and legends also confirmed the fact that intermittent jerks along these major active faults have caused the majority of earthquakes in Myanmar. These seismotectonic processes are still going on. Along these fault zones stand many large urban cities where thick populations live in. Liquefaction is a very considerable factor according to the past events in the water saturated area near the fault zones.
Geomorphologically, Myanmar has two mountainous provinces: namely, the Western Ranges and the Eastern Highland. These provinces have inherently unstable nature among the areas of the country. The steep slopes, unstable geologic conditions and heavy rains combine together to make the mountainous regions one of the most hazard-prone areas in Myanmar. Landslides frequently happens in these regions, disturbing the connection roads and infrastructures rather than rural houses. Moreover, there has been an increase in human settlement in hazard-prone areas as a result of rapid population growth, as well as improvement in accessibility by road and the onset of other infrastructure development. Consequently, natural and man-made disasters are on the increase and each event affects people more than before. Even in central low land between the two mountainous ranges, landslide features occur along the bank of Ayeyarwady River and its tributaries.
There were also records of moderate tsunami generated by two large magnitude earthquakes, which originated in the Andaman-Nicobar Islands. Of course, the tsunami generated by the giant 2004 Sumatra Earthquake also caused moderate causalities in some parts of the Myanmar coast. Thus, it is evident that Myanmar is vulnerable to disaster from moderate and large tsunamis along its long coastal line.
To mitigate loss of lives and damages of properties, the Natural Disaster Mitigation Committee of Myanmar has been formed since 2004. Moreover, Seismic Hazard Zonation Map of Myanmar has already been prepared with the collaboration of engineering geologists, geoscientists and engineers since 2006. During the year of 2006 to 2008, the Myanmar Geosciences Society (MGS) in collaboration with MEC has prepared the preliminary deterministic seismic zonation maps for four seismically hazardous cities.
Although modern seismological instruments and technical improvement are very essential, earthquake resistant design code shall be enhanced by the cooperative works among the scientists and engineers from various organizations. Landslide potential map and tsunami inundation map are going to be established this year. Moreover, to increase the awareness of the geo-disaster, education and knowledge have been given to those who live in hazardous-prone areas by the collaboration of DMH, RRD, MES, MGS, ADPC and Universities in Yangon. Besides, landslide mitigation technology applied in Myanmar and construction of tsunami shelter in coastal areas are also discussed in this paper.
Keywords: Earthquake, tsunamis, active fault, landslide, liquefaction
Geotechnical data synthesis for GIS-based analysis of fault zone geometry and hazard in an urban environment