New structural data along the central part of the Dauki topographic front supports the hypothesis... more New structural data along the central part of the Dauki topographic front supports the hypothesis that the Shillong Plateau is a highly asymmetric south-verging Quaternary anticline driven by a north-dipping blind thrust fault that projects into Bangladesh, south of the topographic front. This thrust-fold is tectonically more important than it appears from the relatively modest accumulated deformation, and may represent a reorganization of the eastern Himalayan front. The Dauki Fault is the most likely source of the 1897 Great Indian Earthquake and poses a hazard to densely populated areas on the Ganges-Brahmaputra Delta region. The sharp linear topographic feature often mapped as the Dauki fault is instead a contact between competent Eocene limestone and much less competent younger clastic units. This contact may be depositional or locally a secondary back thrust. While the Sylhet basin has been rapidly subsiding in the Late Quaternary, the topographic front is marked by raised and...
The great 1762 Arakan earthquake caused subsidence and uplift along 700km of the Arakan coast, an... more The great 1762 Arakan earthquake caused subsidence and uplift along 700km of the Arakan coast, and is thought to derive from a huge megathrust rupture reaching northward onto the southeastern coast of Bangladesh. Paleoseismic investigations were conducted in that area to document effects of that and prior earthquakes. U/Th ages obtained from isochron analysis of uplifted dead coral heads of the Poritesspecies, collected along a south to north transect from the islands east coast reveal at least three growth interruptions caused by abrupt relative sea-level changes within the past 1300 years that we interpret to be associated with megathrust ruptures. The ages show distinct events approximately 250, 900 and 1300 years ago. The youngest of these events corresponds to the 1762 Great Arakan earthquake. The two prior events at ~1100 and 700 AD, suggest an average recurrence interval of 400-600 years. Along the coast of Teknaf, we mapped a ~2m uplifted terrace. Marine shells on top of the...
Many of the world's largest river deltas are sinking due to sediment loading, compaction, and... more Many of the world's largest river deltas are sinking due to sediment loading, compaction, and tectonics, but also recently because of groundwater extraction, hydrocarbon extraction, and reduced aggradation. Little is known, however, about the full spatial variability of subsidence rates in complex delta systems. This study reconstructs subsidence rates in the eastern portion of the Ganges-Brahmaputra Delta (GBD), Bangladesh, covering more than 10,000 km2 at a high spatial resolution of 100 m. The map was produced using Interferometric Synthetic Aperture Radar (InSAR) covering the period 2007 to 2011. Eighteen ALOS (Advanced Land Observing Satellite) PALSAR (Phased-Array L-band SAR) scenes were used to generate 30 interferograms calibrated with GPS. Interferograms were stacked to yield average subsidence rates over the study period. Small Baseline Subset (SBAS)-InSAR was then applied to validate the results against an additional GPS record from Dhaka, Bangladesh. Land subsidence ...
The Assam-Bengal Basin system, located near the eastern syntaxis of the Himalayas and the norther... more The Assam-Bengal Basin system, located near the eastern syntaxis of the Himalayas and the northern end of the Indo-Burman Ranges, has received synorogenic sediments of several kilometres thick from these orogenic belts. These deposits provide valuable information on tectonic events, palaeogeography, and evolution of the sedimentary basin. Studies of heavy minerals document temporal variations in detrital compositions reflecting changes in
ABSTRACT A paleo-seismological study was conducted at Jaflong, Sylhet, Bangladesh, which is on th... more ABSTRACT A paleo-seismological study was conducted at Jaflong, Sylhet, Bangladesh, which is on the eastern part of the Dauki fault. The geomorphology around Jaflong is divided into the Shillong Plateau, the foothills, the lower terraces, and the alluvial plain from north to south. Because the foothills and lower terraces are considered to be uplifted tectonically, an active fault is inferred to the south of the lower terraces. This fault, which branches from the Dauki fault as a foreland migration, is known as the Jaflong fault in this paper. The trench investigation was conducted at the southern edge of the lower terrace. The angular unconformity accompanied by folding, which is thought to be the top of the growth strata, was identified in the trench. An asymmetric anticline with a steep southern limb and gentle northern limb is inferred from the back-tilted lower terrace and the folding of the gravel layer parallel to the lower terrace surface. The timing of the seismic event which formed the folding and unconformity is dated to between AD 840 and 920. The trench investigation at Gabrakhari, on the western part of the Dauki fault, revealed that the Dauki fault ruptured in AD 1548 (Morino et al., 2011). Because the 1897 great Indian earthquake (M ⩾ 8.0; Yeats et al., 1997) was caused by the rupture of the Dauki fault (Oldham, 1899), it is clear that the Dauki fault has ruptured three times in the past one thousand years. The timing of these seismic events coincides with that of the paleo-liquefactions confirmed on the Shillong Plateau. It is essential for the paleo-seismological study of the Dauki fault to determine the surface ruptures of the 1897 earthquake. The Dauki fault might be divided into four rupture segments, the western, central, eastern, and easternmost segments. The eastern and western segments ruptured in AD 840–920 and in 1548, respectively. The 1897 earthquake might have been caused by the rupture of the central segment.
Huge earthquakes generally contribute a major portion of the strain at subduction zones, but are ... more Huge earthquakes generally contribute a major portion of the strain at subduction zones, but are rare, and may thus be overlooked in hazard analysis. The India-Sunda boundary is increasingly oblique to convergence from northern Sumatra to the eastern Himalayan Syntaxis and had not experienced a well-documented great subduction earthquake prior to the Mw9.3 1,300km rupture of 26 Dec 2004. The 500km long Arakan segment north of the 2004 rupture may have ruptured in 1762, when a regional earthquake caused changes in coastal elevation and ejection of sand and water from anticlinal ridges. Further north, we found some evidence for a 1548 event which may have ruptured the 300km long Tripura segment from Chittagong to the Shillong Plateau. In this segment, the subduction zone encounters the huge clastic wedge of the Ganges-Brahmaputra delta, which is prograding onto oceanic or transitional crust. This wedge is being accreted into a wide active foldbelt that extends beyond its topographic e...
The nature and the distribution of the earthquake events in different seismic zones of the countr... more The nature and the distribution of the earthquake events in different seismic zones of the country are intrinsically related to various tectonic elements. The increased frequency of earthquake events in Bangladesh in the last 30 years suggests reviving tectonic activity. In case of severe earthquake and increased probability of earthquakes the risk on the loss of life and damage to the property in Bangladesh will be quite high. Four severest risk zones in the country are inferred those include northern part of Dinajpur, Rangpur, Mymensingh, Sylhet, Tangail, northern part of Dhaka, Khulna, Jessor, Kushtia, and Chittagong. Considering the devastating impact of such impending earthquake on land and society and the lack of adequate infrastructures for earthquake studies, the installation of network of high-sensitivity modern seismographs with all components is immediately needed. Valid predictions of earthquakes can thus be made and warnings are issued in order to minimize loss of lives...
Bangladesh is a country characterized by numerous natural disasters. These natural hazards occur ... more Bangladesh is a country characterized by numerous natural disasters. These natural hazards occur both on the surface (e.g., flooding and river avulsions) and within the subsurface (e.g., earthquakes) (see figure), and both types have been related to regional tectonic activity. Bangladesh is also one of the most highly populated countries in the world with a capital city, Dhaka, host to 15 million people. This urban center is located only 40 km southeast from the Madhupur Tract, a potentially tectonically hazardous region. In order to determine this region’s tectonic hazard potential, recent studies have attempted to detect and identify significant neotectonic signatures of the tract, such as faults, lineaments, and weak zones within the region. Recent earthquake evidence along the proposed Madhupur Fault suggests that the area my be tectonically unstable and vulnerable to further seismicity, placing the fast-growing and densely populated Dhaka city in potential danger (see figure).
The Madhupur Tract is in central Bangladesh, and is surrounded by the Jamuna-Brahmaputra river floodplain. The Madhupur Tract is an exposed Quaternary interfluve between two pathways for the Brahmaputra River. Possible uplift of the Madhupur Tract may have exerted a significant control on the avulsion history of the Jamuna River. The Jamuna river avulsion history is cyclic, with a periodicity of about 1800 years. Within these cycles, the Jamuna’s position has fluctuated between west and east of the Madhupur(Pickering et al., 2013). As this avulsion history is thought to be, at least partly, related to seismicity in the region, future seismicity has the potential to cause future river avulsions and related flooding. It is believed that 1885 Bengal earthquake may have been caused by the rupture of the blind Madhupur fault (see figure) on the western margin of the Madhupur. However, there is no paleoseismological evidence. The principle aim of this research is to identify the location of the Madhupur fault and the connection between fault activity and the avulsion history of the Jamuna River. To this end, we aim to determine, existence of the fault by mapping the local lithology using resistivity, and ultimately shed light of the cause of Jamuna River avulsions.
In the late afternoon of 12 June 1897 in Assam, northeastern India, the earth began to rumble. Th... more In the late afternoon of 12 June 1897 in Assam, northeastern India, the earth began to rumble. The eerie subterranean growl grew louder and louder and after a few minutes the ground began to shake, at fi rst gently then with such violence that tombstones, masonry, and even people were fl ung into the air. The Great Assam Earthquake, estimated as high as magnitude 8.7, claimed 1626 lives. Several days later, a team from the Geological Survey of India set out to map the shattered land. “This was the fi rst time someone had resurveyed after an earthquake,” says Philip England, a seismologist at the University of Oxford in the United Kingdom. Over months of wretched work in monsoon downpours, the surveyors measured an astounding 8-meter uplift on the northern edge of Assam’s Shillong Plateau, extending through the area that today is Bangladesh. Incredulous superiors dismissed the results as erroneous and buried the report.
Dhaka is one of the earthquake-prone cities in the world and probably Dhaka ranks top in the list... more Dhaka is one of the earthquake-prone cities in the world and probably Dhaka ranks top in the list of earthquake vulnerability. There are potential sources of major earthquakes within Bangladesh and its neighboring regions, which may produce earthquakes of magnitudes of 7-9 in the Richter scale. Bangladesh especially Dhaka was severely shocked from local as well as distant earthquakes in the historic past. Dhaka suffered ground shaking of the order III to VIII on the Modified Mercalli scale from both distant and local earthquakes during the historic and the recent times. Dhaka had suffered from earthquakes in the year of 1762, 1812, 1822, 1846, 1885, 1897, 1918,1923, 1930 and 1934 - the most severe earthquakes in recent recorded history. The most vulnerable earthquake areas in Bangladesh cover the whole region that lies east of the Jamuna and Meghna rivers including greater Dhaka, Mymensingh, Comilla, Noakhali, Sylhet, Chittagong and Chittagong Hill Tracts districts. If the Bengal earthquake of magnitude 7 of the year 1885 and the great Indian earthquake of magnitude 8.7 in 1897 were to recur or if an earthquake of magnitude 6 were to occur beneath Dhaka, the situation of Dhaka city with its 12.8 million population living in widespread brick masonry, non-engineered and poorly constructed buildings would be worst than ever in the history of Dhaka. The aftermath of such a possible destructive earthquake could lead to the abandoning of the Dhaka city. Bangladesh as a whole is very vulnerable to earthquake of magnitude more than 5 on the Richter scale because of its geological and tectonic set up. Bangladesh is situated at the junction of three plates of India, Burma and Tibet. The rigid part of the earth’s upper surface, which is 70 km thick, called lithosphere fragmented into major 12 plates is floating on semi viscous fluid. India plate moves 6 cm per year towards north-east while Burma plate moves 2 cm per year towards south-west. The movement of India and Burma plates towards each other is shortening Bangladesh at the rate of 6 millimeter per year.
Introduction:
Dhaka, one of the oldest historical cities in the Indian sub-continent and now the ... more Introduction: Dhaka, one of the oldest historical cities in the Indian sub-continent and now the capital of Bangladesh, is vulnerable to earthquakes. In broad terms, Bangladesh is an earthquake-prone country; its northern and eastern regions in particular are known to be subjected to earthquakes of magnitudes greater than 5 on the Richter scale. The geotectonic set-up of the country, which is located along two of the planet’s active plate boundaries, suggests high probabilities of damaging future earthquakes and the possibility of rarer but extraordinarily large earthquakes that can cause damage far from their epicenters. The juxtaposition of the Himalayan orogen along with its syntaxis northeast of Bangladesh and the convergent BurmaArc plate boundary in the east make this land and Dhaka, in particular, vulnerable to high-magnitude earthquake events. Dhaka, a fast growing and densely populated (12.8 million as of 2008) mega city, poses an extremely high risk because of its population density (45,508 per km2) and innumerable high-rise apartments and office buildings constructed through ignoring the Bangladesh National Building Code (BNBC) and failing to adhere to standard construction practices.According to Earthquake Disaster Risk Index (EDRI) parameters Dhaka is one of the top twenty high earthquake risk cities in the world (Cardona et al., 1999). The hazard that is inferred from tectonic analysis is backed by historic evidence. Bangladesh, a country of multiple natural disaster vulnerabilities, and its capital Dhaka are under the looming threat of cataclysmic earthquakes. Records show that large earthquakes have previously ravaged the country and the neighbouring region several times over the last 450 years.
New structural data along the central part of the Dauki topographic front supports the hypothesis... more New structural data along the central part of the Dauki topographic front supports the hypothesis that the Shillong Plateau is a highly asymmetric south-verging Quaternary anticline driven by a north-dipping blind thrust fault that projects into Bangladesh, south of the topographic front. This thrust-fold is tectonically more important than it appears from the relatively modest accumulated deformation, and may represent a reorganization of the eastern Himalayan front. The Dauki Fault is the most likely source of the 1897 Great Indian Earthquake and poses a hazard to densely populated areas on the Ganges-Brahmaputra Delta region. The sharp linear topographic feature often mapped as the Dauki fault is instead a contact between competent Eocene limestone and much less competent younger clastic units. This contact may be depositional or locally a secondary back thrust. While the Sylhet basin has been rapidly subsiding in the Late Quaternary, the topographic front is marked by raised and...
The great 1762 Arakan earthquake caused subsidence and uplift along 700km of the Arakan coast, an... more The great 1762 Arakan earthquake caused subsidence and uplift along 700km of the Arakan coast, and is thought to derive from a huge megathrust rupture reaching northward onto the southeastern coast of Bangladesh. Paleoseismic investigations were conducted in that area to document effects of that and prior earthquakes. U/Th ages obtained from isochron analysis of uplifted dead coral heads of the Poritesspecies, collected along a south to north transect from the islands east coast reveal at least three growth interruptions caused by abrupt relative sea-level changes within the past 1300 years that we interpret to be associated with megathrust ruptures. The ages show distinct events approximately 250, 900 and 1300 years ago. The youngest of these events corresponds to the 1762 Great Arakan earthquake. The two prior events at ~1100 and 700 AD, suggest an average recurrence interval of 400-600 years. Along the coast of Teknaf, we mapped a ~2m uplifted terrace. Marine shells on top of the...
Many of the world's largest river deltas are sinking due to sediment loading, compaction, and... more Many of the world's largest river deltas are sinking due to sediment loading, compaction, and tectonics, but also recently because of groundwater extraction, hydrocarbon extraction, and reduced aggradation. Little is known, however, about the full spatial variability of subsidence rates in complex delta systems. This study reconstructs subsidence rates in the eastern portion of the Ganges-Brahmaputra Delta (GBD), Bangladesh, covering more than 10,000 km2 at a high spatial resolution of 100 m. The map was produced using Interferometric Synthetic Aperture Radar (InSAR) covering the period 2007 to 2011. Eighteen ALOS (Advanced Land Observing Satellite) PALSAR (Phased-Array L-band SAR) scenes were used to generate 30 interferograms calibrated with GPS. Interferograms were stacked to yield average subsidence rates over the study period. Small Baseline Subset (SBAS)-InSAR was then applied to validate the results against an additional GPS record from Dhaka, Bangladesh. Land subsidence ...
The Assam-Bengal Basin system, located near the eastern syntaxis of the Himalayas and the norther... more The Assam-Bengal Basin system, located near the eastern syntaxis of the Himalayas and the northern end of the Indo-Burman Ranges, has received synorogenic sediments of several kilometres thick from these orogenic belts. These deposits provide valuable information on tectonic events, palaeogeography, and evolution of the sedimentary basin. Studies of heavy minerals document temporal variations in detrital compositions reflecting changes in
ABSTRACT A paleo-seismological study was conducted at Jaflong, Sylhet, Bangladesh, which is on th... more ABSTRACT A paleo-seismological study was conducted at Jaflong, Sylhet, Bangladesh, which is on the eastern part of the Dauki fault. The geomorphology around Jaflong is divided into the Shillong Plateau, the foothills, the lower terraces, and the alluvial plain from north to south. Because the foothills and lower terraces are considered to be uplifted tectonically, an active fault is inferred to the south of the lower terraces. This fault, which branches from the Dauki fault as a foreland migration, is known as the Jaflong fault in this paper. The trench investigation was conducted at the southern edge of the lower terrace. The angular unconformity accompanied by folding, which is thought to be the top of the growth strata, was identified in the trench. An asymmetric anticline with a steep southern limb and gentle northern limb is inferred from the back-tilted lower terrace and the folding of the gravel layer parallel to the lower terrace surface. The timing of the seismic event which formed the folding and unconformity is dated to between AD 840 and 920. The trench investigation at Gabrakhari, on the western part of the Dauki fault, revealed that the Dauki fault ruptured in AD 1548 (Morino et al., 2011). Because the 1897 great Indian earthquake (M ⩾ 8.0; Yeats et al., 1997) was caused by the rupture of the Dauki fault (Oldham, 1899), it is clear that the Dauki fault has ruptured three times in the past one thousand years. The timing of these seismic events coincides with that of the paleo-liquefactions confirmed on the Shillong Plateau. It is essential for the paleo-seismological study of the Dauki fault to determine the surface ruptures of the 1897 earthquake. The Dauki fault might be divided into four rupture segments, the western, central, eastern, and easternmost segments. The eastern and western segments ruptured in AD 840–920 and in 1548, respectively. The 1897 earthquake might have been caused by the rupture of the central segment.
Huge earthquakes generally contribute a major portion of the strain at subduction zones, but are ... more Huge earthquakes generally contribute a major portion of the strain at subduction zones, but are rare, and may thus be overlooked in hazard analysis. The India-Sunda boundary is increasingly oblique to convergence from northern Sumatra to the eastern Himalayan Syntaxis and had not experienced a well-documented great subduction earthquake prior to the Mw9.3 1,300km rupture of 26 Dec 2004. The 500km long Arakan segment north of the 2004 rupture may have ruptured in 1762, when a regional earthquake caused changes in coastal elevation and ejection of sand and water from anticlinal ridges. Further north, we found some evidence for a 1548 event which may have ruptured the 300km long Tripura segment from Chittagong to the Shillong Plateau. In this segment, the subduction zone encounters the huge clastic wedge of the Ganges-Brahmaputra delta, which is prograding onto oceanic or transitional crust. This wedge is being accreted into a wide active foldbelt that extends beyond its topographic e...
The nature and the distribution of the earthquake events in different seismic zones of the countr... more The nature and the distribution of the earthquake events in different seismic zones of the country are intrinsically related to various tectonic elements. The increased frequency of earthquake events in Bangladesh in the last 30 years suggests reviving tectonic activity. In case of severe earthquake and increased probability of earthquakes the risk on the loss of life and damage to the property in Bangladesh will be quite high. Four severest risk zones in the country are inferred those include northern part of Dinajpur, Rangpur, Mymensingh, Sylhet, Tangail, northern part of Dhaka, Khulna, Jessor, Kushtia, and Chittagong. Considering the devastating impact of such impending earthquake on land and society and the lack of adequate infrastructures for earthquake studies, the installation of network of high-sensitivity modern seismographs with all components is immediately needed. Valid predictions of earthquakes can thus be made and warnings are issued in order to minimize loss of lives...
Bangladesh is a country characterized by numerous natural disasters. These natural hazards occur ... more Bangladesh is a country characterized by numerous natural disasters. These natural hazards occur both on the surface (e.g., flooding and river avulsions) and within the subsurface (e.g., earthquakes) (see figure), and both types have been related to regional tectonic activity. Bangladesh is also one of the most highly populated countries in the world with a capital city, Dhaka, host to 15 million people. This urban center is located only 40 km southeast from the Madhupur Tract, a potentially tectonically hazardous region. In order to determine this region’s tectonic hazard potential, recent studies have attempted to detect and identify significant neotectonic signatures of the tract, such as faults, lineaments, and weak zones within the region. Recent earthquake evidence along the proposed Madhupur Fault suggests that the area my be tectonically unstable and vulnerable to further seismicity, placing the fast-growing and densely populated Dhaka city in potential danger (see figure).
The Madhupur Tract is in central Bangladesh, and is surrounded by the Jamuna-Brahmaputra river floodplain. The Madhupur Tract is an exposed Quaternary interfluve between two pathways for the Brahmaputra River. Possible uplift of the Madhupur Tract may have exerted a significant control on the avulsion history of the Jamuna River. The Jamuna river avulsion history is cyclic, with a periodicity of about 1800 years. Within these cycles, the Jamuna’s position has fluctuated between west and east of the Madhupur(Pickering et al., 2013). As this avulsion history is thought to be, at least partly, related to seismicity in the region, future seismicity has the potential to cause future river avulsions and related flooding. It is believed that 1885 Bengal earthquake may have been caused by the rupture of the blind Madhupur fault (see figure) on the western margin of the Madhupur. However, there is no paleoseismological evidence. The principle aim of this research is to identify the location of the Madhupur fault and the connection between fault activity and the avulsion history of the Jamuna River. To this end, we aim to determine, existence of the fault by mapping the local lithology using resistivity, and ultimately shed light of the cause of Jamuna River avulsions.
In the late afternoon of 12 June 1897 in Assam, northeastern India, the earth began to rumble. Th... more In the late afternoon of 12 June 1897 in Assam, northeastern India, the earth began to rumble. The eerie subterranean growl grew louder and louder and after a few minutes the ground began to shake, at fi rst gently then with such violence that tombstones, masonry, and even people were fl ung into the air. The Great Assam Earthquake, estimated as high as magnitude 8.7, claimed 1626 lives. Several days later, a team from the Geological Survey of India set out to map the shattered land. “This was the fi rst time someone had resurveyed after an earthquake,” says Philip England, a seismologist at the University of Oxford in the United Kingdom. Over months of wretched work in monsoon downpours, the surveyors measured an astounding 8-meter uplift on the northern edge of Assam’s Shillong Plateau, extending through the area that today is Bangladesh. Incredulous superiors dismissed the results as erroneous and buried the report.
Dhaka is one of the earthquake-prone cities in the world and probably Dhaka ranks top in the list... more Dhaka is one of the earthquake-prone cities in the world and probably Dhaka ranks top in the list of earthquake vulnerability. There are potential sources of major earthquakes within Bangladesh and its neighboring regions, which may produce earthquakes of magnitudes of 7-9 in the Richter scale. Bangladesh especially Dhaka was severely shocked from local as well as distant earthquakes in the historic past. Dhaka suffered ground shaking of the order III to VIII on the Modified Mercalli scale from both distant and local earthquakes during the historic and the recent times. Dhaka had suffered from earthquakes in the year of 1762, 1812, 1822, 1846, 1885, 1897, 1918,1923, 1930 and 1934 - the most severe earthquakes in recent recorded history. The most vulnerable earthquake areas in Bangladesh cover the whole region that lies east of the Jamuna and Meghna rivers including greater Dhaka, Mymensingh, Comilla, Noakhali, Sylhet, Chittagong and Chittagong Hill Tracts districts. If the Bengal earthquake of magnitude 7 of the year 1885 and the great Indian earthquake of magnitude 8.7 in 1897 were to recur or if an earthquake of magnitude 6 were to occur beneath Dhaka, the situation of Dhaka city with its 12.8 million population living in widespread brick masonry, non-engineered and poorly constructed buildings would be worst than ever in the history of Dhaka. The aftermath of such a possible destructive earthquake could lead to the abandoning of the Dhaka city. Bangladesh as a whole is very vulnerable to earthquake of magnitude more than 5 on the Richter scale because of its geological and tectonic set up. Bangladesh is situated at the junction of three plates of India, Burma and Tibet. The rigid part of the earth’s upper surface, which is 70 km thick, called lithosphere fragmented into major 12 plates is floating on semi viscous fluid. India plate moves 6 cm per year towards north-east while Burma plate moves 2 cm per year towards south-west. The movement of India and Burma plates towards each other is shortening Bangladesh at the rate of 6 millimeter per year.
Introduction:
Dhaka, one of the oldest historical cities in the Indian sub-continent and now the ... more Introduction: Dhaka, one of the oldest historical cities in the Indian sub-continent and now the capital of Bangladesh, is vulnerable to earthquakes. In broad terms, Bangladesh is an earthquake-prone country; its northern and eastern regions in particular are known to be subjected to earthquakes of magnitudes greater than 5 on the Richter scale. The geotectonic set-up of the country, which is located along two of the planet’s active plate boundaries, suggests high probabilities of damaging future earthquakes and the possibility of rarer but extraordinarily large earthquakes that can cause damage far from their epicenters. The juxtaposition of the Himalayan orogen along with its syntaxis northeast of Bangladesh and the convergent BurmaArc plate boundary in the east make this land and Dhaka, in particular, vulnerable to high-magnitude earthquake events. Dhaka, a fast growing and densely populated (12.8 million as of 2008) mega city, poses an extremely high risk because of its population density (45,508 per km2) and innumerable high-rise apartments and office buildings constructed through ignoring the Bangladesh National Building Code (BNBC) and failing to adhere to standard construction practices.According to Earthquake Disaster Risk Index (EDRI) parameters Dhaka is one of the top twenty high earthquake risk cities in the world (Cardona et al., 1999). The hazard that is inferred from tectonic analysis is backed by historic evidence. Bangladesh, a country of multiple natural disaster vulnerabilities, and its capital Dhaka are under the looming threat of cataclysmic earthquakes. Records show that large earthquakes have previously ravaged the country and the neighbouring region several times over the last 450 years.
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Papers by Syed Humayun Akhter
The Madhupur Tract is in central Bangladesh, and is surrounded by the Jamuna-Brahmaputra river floodplain. The Madhupur Tract is an exposed Quaternary interfluve between two pathways for the Brahmaputra River. Possible uplift of the Madhupur Tract may have exerted a significant control on the avulsion history of the Jamuna River. The Jamuna river avulsion history is cyclic, with a periodicity of about 1800 years. Within these cycles, the Jamuna’s position has fluctuated between west and east of the Madhupur(Pickering et al., 2013). As this avulsion history is thought to be, at least partly, related to seismicity in the region, future seismicity has the potential to cause future river avulsions and related flooding. It is believed that 1885 Bengal earthquake may have been caused by the rupture of the blind Madhupur fault (see figure) on the western margin of the Madhupur. However, there is no paleoseismological evidence. The principle aim of this research is to identify the location of the Madhupur fault and the connection between fault activity and the avulsion history of the Jamuna River. To this end, we aim to determine, existence of the fault by mapping the local lithology using resistivity, and ultimately shed light of the cause of Jamuna River avulsions.
8.7, claimed 1626 lives. Several days later, a team from the Geological Survey of India set out to map the shattered land. “This was the fi rst time someone had resurveyed after an earthquake,” says Philip England, a seismologist at the University of Oxford in the United Kingdom. Over months of wretched work in monsoon downpours, the surveyors measured an astounding 8-meter uplift on the northern edge of Assam’s Shillong Plateau, extending through the area that today is Bangladesh. Incredulous superiors dismissed the results as erroneous and buried the report.
Dhaka, one of the oldest historical cities in the Indian sub-continent and now the capital of Bangladesh, is vulnerable to earthquakes. In broad terms, Bangladesh is an earthquake-prone country; its northern and eastern regions in particular are known to be subjected to earthquakes of magnitudes greater than 5 on the Richter scale. The geotectonic set-up of the country, which is located along two of the planet’s active plate boundaries, suggests high probabilities of damaging future earthquakes and the possibility of rarer but extraordinarily large earthquakes that can cause damage far from their epicenters. The juxtaposition of the Himalayan orogen along with its syntaxis northeast of Bangladesh and the convergent BurmaArc plate boundary in the east make this land and Dhaka, in particular, vulnerable to high-magnitude earthquake events.
Dhaka, a fast growing and densely populated (12.8 million as of 2008) mega city, poses an extremely high risk because of its population density (45,508 per km2) and innumerable high-rise apartments and office buildings constructed through ignoring the Bangladesh National Building Code (BNBC) and failing to adhere to standard construction practices.According to Earthquake Disaster Risk Index (EDRI) parameters Dhaka is one of the top twenty high earthquake risk cities in the world (Cardona et al., 1999). The hazard that is inferred from tectonic analysis is backed by historic evidence. Bangladesh, a country of multiple natural disaster vulnerabilities, and its capital Dhaka are under the looming threat of cataclysmic earthquakes. Records show that large earthquakes have previously ravaged the country and the neighbouring region several times over the last 450 years.
The Madhupur Tract is in central Bangladesh, and is surrounded by the Jamuna-Brahmaputra river floodplain. The Madhupur Tract is an exposed Quaternary interfluve between two pathways for the Brahmaputra River. Possible uplift of the Madhupur Tract may have exerted a significant control on the avulsion history of the Jamuna River. The Jamuna river avulsion history is cyclic, with a periodicity of about 1800 years. Within these cycles, the Jamuna’s position has fluctuated between west and east of the Madhupur(Pickering et al., 2013). As this avulsion history is thought to be, at least partly, related to seismicity in the region, future seismicity has the potential to cause future river avulsions and related flooding. It is believed that 1885 Bengal earthquake may have been caused by the rupture of the blind Madhupur fault (see figure) on the western margin of the Madhupur. However, there is no paleoseismological evidence. The principle aim of this research is to identify the location of the Madhupur fault and the connection between fault activity and the avulsion history of the Jamuna River. To this end, we aim to determine, existence of the fault by mapping the local lithology using resistivity, and ultimately shed light of the cause of Jamuna River avulsions.
8.7, claimed 1626 lives. Several days later, a team from the Geological Survey of India set out to map the shattered land. “This was the fi rst time someone had resurveyed after an earthquake,” says Philip England, a seismologist at the University of Oxford in the United Kingdom. Over months of wretched work in monsoon downpours, the surveyors measured an astounding 8-meter uplift on the northern edge of Assam’s Shillong Plateau, extending through the area that today is Bangladesh. Incredulous superiors dismissed the results as erroneous and buried the report.
Dhaka, one of the oldest historical cities in the Indian sub-continent and now the capital of Bangladesh, is vulnerable to earthquakes. In broad terms, Bangladesh is an earthquake-prone country; its northern and eastern regions in particular are known to be subjected to earthquakes of magnitudes greater than 5 on the Richter scale. The geotectonic set-up of the country, which is located along two of the planet’s active plate boundaries, suggests high probabilities of damaging future earthquakes and the possibility of rarer but extraordinarily large earthquakes that can cause damage far from their epicenters. The juxtaposition of the Himalayan orogen along with its syntaxis northeast of Bangladesh and the convergent BurmaArc plate boundary in the east make this land and Dhaka, in particular, vulnerable to high-magnitude earthquake events.
Dhaka, a fast growing and densely populated (12.8 million as of 2008) mega city, poses an extremely high risk because of its population density (45,508 per km2) and innumerable high-rise apartments and office buildings constructed through ignoring the Bangladesh National Building Code (BNBC) and failing to adhere to standard construction practices.According to Earthquake Disaster Risk Index (EDRI) parameters Dhaka is one of the top twenty high earthquake risk cities in the world (Cardona et al., 1999). The hazard that is inferred from tectonic analysis is backed by historic evidence. Bangladesh, a country of multiple natural disaster vulnerabilities, and its capital Dhaka are under the looming threat of cataclysmic earthquakes. Records show that large earthquakes have previously ravaged the country and the neighbouring region several times over the last 450 years.