Missouri University of Science and Technology Scholars' Mine International Conference on Case Histories in (2008) - Sixth International Conference on Case Geotechnical Engineering Histories in Geotechnical Engineering 14 Aug 2008, 4:30pm - 6:00pm Prevention, Mitigation and Engineering Response for Geohazard in Thailand Adichat Surinkum Department of Mineral Resources, Ratchathewi, Bangkok, Thailand Worawoot Tantiwanit Department of Mineral Resources, Ratchathewi, Bangkok, Thailand Jarin Tulyatid Department of Mineral Resources, Ratchathewi, Bangkok, Thailand Follow this and additional works at: https://scholarsmine.mst.edu/icchge Part of the Geotechnical Engineering Commons Recommended Citation Surinkum, Adichat; Tantiwanit, Worawoot; and Tulyatid, Jarin, "Prevention, Mitigation and Engineering Response for Geohazard in Thailand" (2008). 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PREVENTION, MITIGATION AND ENGINEERING RESPONSE FOR GEOHAZARD IN THAILAND Adichat SURINKUM Worawoot TANTIWANIT Jarin TULYATID Department of Mineral Resources Department of Mineral Resources Department of Mineral Resources Rama VI Rd., Ratchathewi, Rama VI Rd., Ratchathewi, Rama VI Rd., Ratchathewi, Bangkok, Thailand, 10400 Bangkok, Thailand, 10400 Bangkok, Thailand, 10400 ABSTRACT Thailand is situated in SE Asia where most of the area has been under the influence of monsoonal type of weather. Geological settings of the country is believed to be the result of the collision between Indian and Eurasian plates. The collision has great influences on the topographic, weather and tectonic activities of the area for a long time. These factors are closely related to a number of serious geohazards of the area. Such geohazards include landslide and tsunami caused by a large distant earthquake along the Indian – Eurasian subduction zone. Important geohazard cases in Thailand have been discussed and landslide is focused in order to make an optimum risks assessment. There are three main landslide events occurred in Thailand. These landslides occurred in Nakhon Si Thammarat province in the south; Phetchabun province in the northeast; and Tak province in the west. The 2004’s Tsunami event was also unexpected one to a great number of people who live along the Andaman shorelines of the country. These events have generated awareness on landslide geohazard to the nation because it took many lives and damaged properties. As one of the key organization working on geohazard, the Department of Mineral Resources has carried out study programs in order to gain better understanding of such events and then set up activities for the prevention and mitigation for it via engineering approach. Most of our works are based upon not only a scientific approach but also concepts of people’s participatory. We have set up landslide warning networks for both local and regional ones for the high risked areas throughout the country. For tsunami, we have set up our measures via education, information transmission and evacuation plan for high risked areas. Our work has created awareness among people who have been or potentially been effected by such hazards to be well prepared for the event that has yet to come. INTRODUCTION The great Sumatra earthquake occurred on the 26 December 2004 with the epicenter off the west coast of the Sumatra, In recent years, there have been an increasing number of Indonesia. The earthquake triggered a series of devastating studies on tragic events related to geological processes tsunami along the coasts of most landmasses bordering the especially in the tropical countries. Such processes include Indian Ocean, killing a large numbers of people and earthquake, tsunami, sinkholes, flash-flood, landslides, land inundating coastal communities across South and Southeast subsidence and erosion. Asia including parts of Indonesia, Sri Lanka, India and Thailand. Many places in the region especially in the Thai Thailand is located in Southeast Asia between latitudes 5° 37´ Peninsula have been affected by the ground shaking after the N and 20° 27´N and longitudes 97° 22´E and 105° 37´E (Fig. earthquake. The earthquake has resulted in the adjustment of 1, inset). The country has been under the influence of its microplates of the region that then triggered a number of geological setting resulted from the still-active collision of the sinkhole and landslide to occur in the region as a consequence. Indian and Eurasian Plates, which began 50 Ma ago (Fig. 1). The region has actually been under the heavy rainfall, high This “extrusion” of microplates toward the east and southeast rates of ground weathering and erosion process, and a number has resulted in the on-going development of present of problems, which of them are caused by human activities. topographic settings that also have influenced the formation Deforestation and the development over the forest area also and the intensification of monsoonal weather type of Thailand speed up all geohazards, i.e., flash-flood and landslide; and Southeast Asia region. sinkholes; land subsidence; river and shoreline erosion. Such geohazards have now become a national issue that needs to be Paper No. 2.29 1 well handled as soon as possible to prevent further lost of lives up with a standard way of life in the area where geohazard is a and properties of the local people. threat to the community are true challenges to the DMR’s work. It normally takes a long time for the affected As one of the key offices responsible for the prevention and communities to achieve help from the central government. mitigation of the national geohazards, the Department of Mineral Resources (DMR) has worked on the issue for over a Geohazard management varies from one type to another, as decade. Normally, the central government responds to the well as on a case by case basis. In the flash-flood and landslide event through the building of network in the local areas being case, most of the help are in the form of new constructions for roads, bridges and structures to stable slopes in accordance to the engineering geology of the area. These structures are still located in the risked areas where geohazards always occur and we know that, sooner or later, these structures will be wiped out by the force of nature. In order to lay a good foundation on works related to the prevention and mitigation to the geohazards in Thailand, DMR has now tried to make the best out of our limited resources in order to sustain the geohazard management system of the local communities distributed throughout the country. A new concept has been developed under certain key concepts, which are: geological knowledge as a strong foundation, best engineering geological practice; HM King Bhumibhol’s sufficient economy; and living in harmony with nature. This paper summarizes important geohazards of Thailand and introduces the new concept, “Living in harmony with nature”, with an example of the pilot project of the DMR to test out. The result is very convincing and will be applied to other hazardous areas of the country in the near future. GEOLOGIC AND TECTONIC SETTINGS Several authors have reviewed the geology of Thailand (Suensilpong et al., 1978; Chonglakmanee et al., 1983; Bunopas, 1981; Department of Mineral Resources, 2002). The geological map of Thailand (DMR, 2002) shows that the Fig. 1 Schematic map illustrating postulated post-Paleozoic western mountainous terranes contain a variety of igneous, “extrusion tectonics” and present-day plate metamorphic and sedimentary rocks of various ages. configurations in eastern Asia (modified after Precambrian metasediments and early Paleozoic sandstone Tapponnier et al., 1982). Numbers associated within and limestone are exposed in the western part only. Thick open arrows refer to extrusion phases (1: 50-20 Ma; middle Paleozoic sedimentary and volcanic rocks crop out in 2: <20 Ma). Arrows on faults in Thailand possibly the eastern part (Bunopas, 1981) Permo-Triassic and post – correspond to Permo-Triassic motions (Polachan et Triassic granite plutons are found to have intruded al., 1991). The reversed movement on these faults Precambrian sedimentary rocks and early Paleozoic rocks in may have possibly occurred since mid-Tertiary time the western mountain terrain. These rocks also crop out in the (Tapponnier et al., 1986. The inset map shows the eastern and southern parts of the country. Thick Triassic area of Thailand with the locations of the major fault marine sedimentary sequences are also found in the eastern zones and Chao Phraya Central Floodplain (C). and western parts of the mountain range. affected by natural hazards. The network helps on the monitoring the geohazard situation. DMR also gives technical To the east of the central mountains, Mesozoic rocks of advices and supports to the local government and Jurassic and Early Cretaceous red sandstone cover the Khorat administration