Bangladesh Tsunami Map
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STATE OF EARTHQUAKE AND TSUNAMI VULNERABILITY OF BANGLADESH: SOME GEO-SCIENTIFIC STRATEGIES FOR RISK REDUCTION Mir Fazlul Karim1, Sirajur Rahman Khan1, AKM Kourshed Alam1 and Nasima Begum2 Geological Survey of Bangladesh, Dhaka,... more
STATE OF EARTHQUAKE AND TSUNAMI VULNERABILITY OF BANGLADESH: SOME GEO-SCIENTIFIC STRATEGIES FOR RISK REDUCTION
Mir Fazlul Karim1, Sirajur Rahman Khan1, AKM Kourshed Alam1 and Nasima Begum2
Geological Survey of Bangladesh, Dhaka, Bangladesh
Extended Abstract
After the Andaman-Sumatra earthquake of 26 December 2004 it has become essential to re-evaluate the regional and global seismogenic hazard maps. The devastating megathrust earthquake generated a massive tsunami causing death of millions and destruction of huge livelihood in the Indian Ocean region. The 9.0 magnitude (RS) earthquake has made unprecedented changes in the seafloor configuration, mostly along the India and Burma plate boundaries. Following the event of this extraordinary earthquake an attempt is made by the Geological Survey of Bangladesh to investigate the reasons of insignificant affects in the coastal belt and delineate the state of tsunami vulnerability of the country. The unique seafloor configuration, consisting of about 200 km continental shelf helped to deflect the massive tsunami waves that strike the continental slope after two and half hours of the main thrust.
Geologically Bangladesh is a very young landmass having an active delta building system into the tectonic framework of Bengal basin. Due to the geographical location, pattern of geomorphic facets and an active tectonic plate interface along the eastern boundary, the country has always been prone to various natural hazards. The geodynamic adjustment due to tectonic plate movements along the interfaces of Indian and Eurasian Plates stretching from the Himalayan Mountains to Sunda Trench caused the country to be a part of a most active platelet (Bengal Platelet?).
Though the frequency of large earthquakes is low, the country and the surrounding region experienced number of great earthquakes during the last century. Most of the epicenters of these great earthquakes are located outside the territory. The occurrence of these earthquakes and the recent Asia Earthquake of December 26, 2004 make the landmass to be exposed to most deadliest and destructive natural hazards related to regional tectonics. Fortunately the physical damages due to these tectonic hazards are very limited and insignificant in Bangladesh. But at every event tremendous panic and concern develop throughout the country causing disruption in normal activity. Similarly after the Andaman-Sumatra tsunami the nation was uncertain about the Indian Ocean situation due to lack of any seismic observatory and acceptable monitoring system. Manifold increase in population, urban clusters and rapid infrastructure development has increased the earthquake risk scenario of the country. This paper presents the state of earthquake and tsunami vulnerability of Bangladesh for identification of some geo-scientific strategies for risk reduction and disaster management.
A modified Seismic Hazard Map and a Tsunami Vulnerability Map of Bangladesh is proposed in this paper. The maps are prepared by considering all possible correlations of tectonic framework and basin configuration, geological boundary condition and ground characteristics. The country is divided into six seismic hazard zones in this map and into three tsunami vulnerable coastal belts.
Infrequent occurrence of tsunamis in the Bay of Bengal kept the geoscientists of this region almost unconcerned about the potentiality of tsunami hazard. There are some evidences of Paleo-Tsunamis and low height tsunamis. So far evidences of devastating tsunamis are not available but threats of tsunamis in the coastal belt of the country cannot be ruled out. The 200 km long continental shelf is possibly susceptible to earthquakes and landslide / slump failures along the margins of continental slopes. These locations are extremely potential for generation of local tsunamis. Unfortunately the local tsunamis are more destructive than regional tsunamis as the time difference between the tsunami generation and arrival time at the coastal livelihood is very short.
Considering the state of tsunami vulnerability and potential seismic sources the coastal belt of Bangladesh can be divided into three Tsunami Vulnerability Coastal Belts.
1. Tsunami Vulnerability Belt - I of Chittagong-Teknaf coastline – Most vulnerable.
The intra-deltaic coastline is very close to the tectonic interface if Indian and Burmese plates. The active Andaman-Nicobar fault system is often capable to produce tsunami waves.
2. Tsunami Vulnerability Belt - II of Sundarban-Barisal coastline – Moderately vulnerable. This old deltaic belt is extremely vulnerable to local tsunamis due to presence of Swatch of No Ground.
3. Tsunami Vulnerability Belt - III of Barisal-Sandwip estuarine coastline – Low vulnerability due to presence numerous islets and shoals.
However, for sustainable development processes of the country it is essential that a rapid seismic observatory system be developed, as it is an integral part of tsunami early warning system. Inter-organizational and regional cooperation of the warning systems for detection of local, regional and ocean wide tsunamis is prime requisite to reduce earthquake and tsunami risk in the region. A multi-professional research activity and action plan will help in capacity building, education and awareness of the people of Bangladesh and thus an efficient disaster management system will be ensured.
Email: mfkarimazad@gmail.com
1 Director, Geological Survey of Bangladesh
2 Assistant Director, Geological Survey of Bangladesh
2005, Dhaka, Bangladesh
Mir Fazlul Karim1, Sirajur Rahman Khan1, AKM Kourshed Alam1 and Nasima Begum2
Geological Survey of Bangladesh, Dhaka, Bangladesh
Extended Abstract
After the Andaman-Sumatra earthquake of 26 December 2004 it has become essential to re-evaluate the regional and global seismogenic hazard maps. The devastating megathrust earthquake generated a massive tsunami causing death of millions and destruction of huge livelihood in the Indian Ocean region. The 9.0 magnitude (RS) earthquake has made unprecedented changes in the seafloor configuration, mostly along the India and Burma plate boundaries. Following the event of this extraordinary earthquake an attempt is made by the Geological Survey of Bangladesh to investigate the reasons of insignificant affects in the coastal belt and delineate the state of tsunami vulnerability of the country. The unique seafloor configuration, consisting of about 200 km continental shelf helped to deflect the massive tsunami waves that strike the continental slope after two and half hours of the main thrust.
Geologically Bangladesh is a very young landmass having an active delta building system into the tectonic framework of Bengal basin. Due to the geographical location, pattern of geomorphic facets and an active tectonic plate interface along the eastern boundary, the country has always been prone to various natural hazards. The geodynamic adjustment due to tectonic plate movements along the interfaces of Indian and Eurasian Plates stretching from the Himalayan Mountains to Sunda Trench caused the country to be a part of a most active platelet (Bengal Platelet?).
Though the frequency of large earthquakes is low, the country and the surrounding region experienced number of great earthquakes during the last century. Most of the epicenters of these great earthquakes are located outside the territory. The occurrence of these earthquakes and the recent Asia Earthquake of December 26, 2004 make the landmass to be exposed to most deadliest and destructive natural hazards related to regional tectonics. Fortunately the physical damages due to these tectonic hazards are very limited and insignificant in Bangladesh. But at every event tremendous panic and concern develop throughout the country causing disruption in normal activity. Similarly after the Andaman-Sumatra tsunami the nation was uncertain about the Indian Ocean situation due to lack of any seismic observatory and acceptable monitoring system. Manifold increase in population, urban clusters and rapid infrastructure development has increased the earthquake risk scenario of the country. This paper presents the state of earthquake and tsunami vulnerability of Bangladesh for identification of some geo-scientific strategies for risk reduction and disaster management.
A modified Seismic Hazard Map and a Tsunami Vulnerability Map of Bangladesh is proposed in this paper. The maps are prepared by considering all possible correlations of tectonic framework and basin configuration, geological boundary condition and ground characteristics. The country is divided into six seismic hazard zones in this map and into three tsunami vulnerable coastal belts.
Infrequent occurrence of tsunamis in the Bay of Bengal kept the geoscientists of this region almost unconcerned about the potentiality of tsunami hazard. There are some evidences of Paleo-Tsunamis and low height tsunamis. So far evidences of devastating tsunamis are not available but threats of tsunamis in the coastal belt of the country cannot be ruled out. The 200 km long continental shelf is possibly susceptible to earthquakes and landslide / slump failures along the margins of continental slopes. These locations are extremely potential for generation of local tsunamis. Unfortunately the local tsunamis are more destructive than regional tsunamis as the time difference between the tsunami generation and arrival time at the coastal livelihood is very short.
Considering the state of tsunami vulnerability and potential seismic sources the coastal belt of Bangladesh can be divided into three Tsunami Vulnerability Coastal Belts.
1. Tsunami Vulnerability Belt - I of Chittagong-Teknaf coastline – Most vulnerable.
The intra-deltaic coastline is very close to the tectonic interface if Indian and Burmese plates. The active Andaman-Nicobar fault system is often capable to produce tsunami waves.
2. Tsunami Vulnerability Belt - II of Sundarban-Barisal coastline – Moderately vulnerable. This old deltaic belt is extremely vulnerable to local tsunamis due to presence of Swatch of No Ground.
3. Tsunami Vulnerability Belt - III of Barisal-Sandwip estuarine coastline – Low vulnerability due to presence numerous islets and shoals.
However, for sustainable development processes of the country it is essential that a rapid seismic observatory system be developed, as it is an integral part of tsunami early warning system. Inter-organizational and regional cooperation of the warning systems for detection of local, regional and ocean wide tsunamis is prime requisite to reduce earthquake and tsunami risk in the region. A multi-professional research activity and action plan will help in capacity building, education and awareness of the people of Bangladesh and thus an efficient disaster management system will be ensured.
Email: mfkarimazad@gmail.com
1 Director, Geological Survey of Bangladesh
2 Assistant Director, Geological Survey of Bangladesh
2005, Dhaka, Bangladesh