According to a geologist, Bangladesh is located in the northeastern part of the Indian sub-continent at the head of the Bay of Bengal. Tectonically, it lies on the northeastern Indian plate near the edge of the Indian carton and at the junction of three tectonic plates - the Indian Plate, the Eurasian Plate and the Burmese microplate. These form two long active tectonic structures where plates converge - the India-Eurasia plate boundary to the north forming the Himalaya Arc, and the India-Burma plate boundary to the east forming the Burma Arc. Bangladesh belongs to the Alpide-Himalayas seismic belt with low earthquake frequency. The geologist, however, said the Indian plate is moving 6cm each year towards the northeast, and sub-ducting under the Eurasian plate at 45mm and the Burmese plate at 35mm in the north and east respectively each year. This continuous motion is taken up by active faults. The probability of an earthquake from a given fault depends on the rate of motion and on the time since the last rupture. Active faults of regional scale capable of generating moderate to great earthquakes are present in and around Bangladesh. These include the Dauki fault, about 300km long trending east-west and located along the southern edge of the Shillong Plateau (Meghalaya- Bangladesh border), the 150km long Madhupur fault trending north-south situated between Madhupur Tract and Jamuna flood plain, the Assam-Sylhet fault, about 300km long trending northeast to southwest located in the southern Surma basin, and the Chittagong-Myanmar plate boundary fault, about 800km long running parallel to the Chittagong-Myanmar coast. A leading disaster watchdog has ranked Bangladesh as the world's sixth "high disaster risk country" in terms of its exposure to typhoons, earthquake and tsunamis. The German-based United Nations University (UNU) Institute for Environment and Human Security (UNU-EHS) in its 'World Risk Report-2011' said Bangladesh ranked second in its risk index in Asia after the Philippines. A key feature of the report, developed by UNU-EHS, calculates and compares risk values for 173 countries worldwide, while ranking regions and countries facing the high disaster risk. It evaluates the interactions between exposure to natural hazards and climate change, and factors of social vulnerability, including levels of poverty, education, food security and governance. The 15 high risk countries respectively are Vanuatu, Tonga, Philippines, Solomon Islands, Guatemala, Bangladesh, Timor-Leste, Costa Rica, Cambodia, El Salvador, Nicaragua, Papua New Guinea, Madagascar, Brunei Darussalam and Afghanistan. Due to the lack of sophisticated earthquake monitoring equipment and facilities in Bangladesh, the level of earthquake activities is poorly defined. As a result, data on micro- seismicity is totally missing, although such activities are quite frequent. The distribution of all major earthquakes recorded and reported in and around Bangladesh is presented in table 1. The table shows that there has not been any major earthquake in Bangladesh for the last 50 years. The return period of a major earthquake with a magnitude of 6.8 is 50 years, while that of a magnitude 7.4 is 100 years. The probabilities of occurrence of such tremors are 98 and 99 per cent respectively. An earthquake of such magnitude is forecast in Bangladesh by 2003. Major seismic sources for the region are Assam fault zone, Tripura fault zone, Sub- Dauki fault zone and Bogra fault zone. These faults are capable of producing earthquakes of magnitudes 8.0, 7.0, 7.3 and 7.0 Richter respectively. Table 1. List of major earthquakes affecting Bangladesh Date Name of the earthquake (Magnitud-Richter) Epicentral distance from Dhaka (km) January 10, 1869 Cachar Earthquake 7.5 250 July 14, 1885 Bengal Earthquake 7.0 170 June 12, 1897Great Indian Earthquake8.7 230 July 8, 1918 Srimongol Earthquake 7.6 150 July 3, 1930 Dhubri Earthquake 7.1 250 January 15, 1934 Bihar-Nepal Earthquake 8.3 510 August 15, 1950 Assam earthquake 8.5 780