2011 Burma earthquake
Encyclopedia
The 2011 Burma earthquake was a 6.8 magnitude earthquake
on 24 March 2011 that had its epicenter
in the east of Shan State
in Burma (Myanmar) with a hypocenter
10 km deep. It had two aftershock
s, one of magnitude 4.8, another at magnitude 5.4 and two subsequent shock at magnitude 5.0 and 6.2. The quake's epicentre was 70 miles from the northern Thai city of Chiang Rai
, north of Mae Sai
and southeast of Kentung.
between the northward moving Indo-Australian Plate
and the Eurasian Plate
, which created the Arakan Yoma
mountains. In this zone of highly oblique collision, most of the motion is accommodated by the north-south trending Sagaing fault
, a major dextral (right lateral) strike-slip fault that runs through the western and central part of Burma. The remaining component of shortening across this zone causes distributed deformation of eastern Burma and Thailand extending into Laos. This deformation is partly accommodated by a set of southwest-northeast trending sinistral (left lateral) strike-slip faults. The faults closest to the epicenter of the earthquake are the Mae Chan
and Nam Ma faults. The focal mechanism
for this earthquake is consistent with left-lateral movement on one of these faults, away from the main zones of seismic activity in Burma. Other recent significant earthquakes in this area included the 2011 Yunnan earthquake
and the 2007 Laos earthquake
. According to the Earth Observatory of Singapore, it appears likely that the earthquake was caused by motion on the western segment of the Nan Ma Fault.
, including a child, as well as Tarpin to its north, both in Shan State
, northeastern Burma. Another person was killed in Mae Sai
, Thailand, near the Burmese border. At least three injuries were reported in Burma.
After sunrise, the casualty toll increased to 24 in Burma, in addition to the one fatality in Thailand. Officials warned that the death toll is likely to rise. Later, death toll rose to 74 killed in Burma and 1 in Thailand, while 111 people were injured. In Tarlay, located between Tachileik and Mong Hpyak, at least 40 were killed when 130 houses collapsed. Vertical displacement
of 1.5 metres in subsidence
was observed in the area.
The Bangkok Post reported on 27 March 2011 that the death toll was "over 150", which is double the official figure of 75.
, Menghai County
in Yunnan
, Nanning
in Guangxi Zhuang Autonomous Region, and in Hanoi
of Vietnam
. At least one bridge is reported collapsed in Myanmar. In total, 390 residential homes, 14 monasteries and 9 government buildings were destroyed. In Monglin, at least 128 homes were reduced to rubble. According to the United States Geological Survey
's population exposure data, the final damages from the earthquake are most likely to be slightly under USD $100 million.
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
on 24 March 2011 that had its epicenter
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
in the east of Shan State
Shan State
Shan State is a state of Burma . Shan State borders China to the north, Laos to the east, and Thailand to the south, and five administrative divisions of Burma in the west. Largest of the 14 administrative divisions by land area, Shan State covers 155,800 km², almost a quarter of the total...
in Burma (Myanmar) with a hypocenter
Hypocenter
The hypocenter refers to the site of an earthquake or a nuclear explosion...
10 km deep. It had two aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
s, one of magnitude 4.8, another at magnitude 5.4 and two subsequent shock at magnitude 5.0 and 6.2. The quake's epicentre was 70 miles from the northern Thai city of Chiang Rai
Chiang Rai
-Demographics:Official Population count: According to the Thailand National Statistical Office, as of September 2010, Chiang Rai municipal district has a population of 199,699...
, north of Mae Sai
Mae Sai
Mae Sai is the northernmost district of Chiang Rai Province in northern Thailand. The town of Mae Sai is a major border crossing between Thailand and Burma...
and southeast of Kentung.
Geology
The earthquake occurred in an area of complex tectonics caused by the continuing collisionContinental collision
Continental collision is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together...
between the northward moving Indo-Australian Plate
Indo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters...
and the Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
, which created the Arakan Yoma
Arakan Yoma
The Arakan Mountains is a mountain range in western Burma , between the coast of Rakhine State and the Central Burma Basin, in which flows the Irrawaddy River...
mountains. In this zone of highly oblique collision, most of the motion is accommodated by the north-south trending Sagaing fault
Sagaing fault
The Sagaing Fault is a major fault in Myanmar, a continental transform fault between the Indian plate and Sunda Plate that connects spreading centers in the Andaman Sea and the continental convergence zone along the Himalayan front...
, a major dextral (right lateral) strike-slip fault that runs through the western and central part of Burma. The remaining component of shortening across this zone causes distributed deformation of eastern Burma and Thailand extending into Laos. This deformation is partly accommodated by a set of southwest-northeast trending sinistral (left lateral) strike-slip faults. The faults closest to the epicenter of the earthquake are the Mae Chan
Mae Chan Fault
Mae Chan Fault is a east-west strike fault in Northern Thailand, responsible for a 6.3 magnitude quake on May 16, 2007 that caused property damage in the provincial capital of Chiang Rai A part of it stretches from Mae Chan to Mae Ai for 40 km along the highway, then goes through Fang, Chiang...
and Nam Ma faults. The focal mechanism
Focal mechanism
The focal mechanism of an earthquake describes the inelastic deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution...
for this earthquake is consistent with left-lateral movement on one of these faults, away from the main zones of seismic activity in Burma. Other recent significant earthquakes in this area included the 2011 Yunnan earthquake
2011 Yunnan earthquake
The 2011 Yunnan earthquake was a 5.4 magnitude earthquake that occurred on 10 March 2011 at 12:58 CST, with its epicenter in Yingjiang County, Yunnan, People's Republic of China, near the Burmese border. A total of 26 people died and 313 were injured with 133 in serious condition...
and the 2007 Laos earthquake
2007 Laos earthquake
At 3.59 p.m. on May 16, 2007, the Laos Earthquake, a magnitude 6.1 earthquake with the epicentre at 20.5N, 100.8E , struck Laos and northern Thailand. Tremors was felt as far as Yunnan, People's Republic of China, Hanoi, Vietnam and Bangkok, Thailand....
. According to the Earth Observatory of Singapore, it appears likely that the earthquake was caused by motion on the western segment of the Nan Ma Fault.
Casualties
Early reports suggested that at least 10 people were killed by quake-triggered landslides in the town of TachileikTachileik
Tachileik , is a border town in the Shan State of eastern Burma . It is the administrative seat of Tachileik Township and Tachileik District.-History:...
, including a child, as well as Tarpin to its north, both in Shan State
Shan State
Shan State is a state of Burma . Shan State borders China to the north, Laos to the east, and Thailand to the south, and five administrative divisions of Burma in the west. Largest of the 14 administrative divisions by land area, Shan State covers 155,800 km², almost a quarter of the total...
, northeastern Burma. Another person was killed in Mae Sai
Mae Sai
Mae Sai is the northernmost district of Chiang Rai Province in northern Thailand. The town of Mae Sai is a major border crossing between Thailand and Burma...
, Thailand, near the Burmese border. At least three injuries were reported in Burma.
After sunrise, the casualty toll increased to 24 in Burma, in addition to the one fatality in Thailand. Officials warned that the death toll is likely to rise. Later, death toll rose to 74 killed in Burma and 1 in Thailand, while 111 people were injured. In Tarlay, located between Tachileik and Mong Hpyak, at least 40 were killed when 130 houses collapsed. Vertical displacement
Vertical displacement
In tectonics, vertical displacement is the shifting of land in a vertical direction, resulting in a permanent change in elevation.Two types of vertical displacement are uplift, an increase in elevation, and subsidence, a decrease in elevation....
of 1.5 metres in subsidence
Subsidence
Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation...
was observed in the area.
The Bangkok Post reported on 27 March 2011 that the death toll was "over 150", which is double the official figure of 75.
Aftermath
Temporary evacuations of tall buildings took place in Chiang RaiChiang Rai
-Demographics:Official Population count: According to the Thailand National Statistical Office, as of September 2010, Chiang Rai municipal district has a population of 199,699...
, Menghai County
Menghai County
Menghai County is a county under the jurisdiction of Xishuangbanna Dai Autonomous Prefecture, Yunnan province, China.-Transport:*Nearest airport is Xishuangbanna Gasa*China National Highway 214-Further reading:...
in Yunnan
Yunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
, Nanning
Nanning
Nanning is the capital of the Guangxi Zhuang Autonomous Region in southern China. It is known as the "Green City" because of its abundance of lush tropical foliage.-History:...
in Guangxi Zhuang Autonomous Region, and in Hanoi
Hanoi
Hanoi , is the capital of Vietnam and the country's second largest city. Its population in 2009 was estimated at 2.6 million for urban districts, 6.5 million for the metropolitan jurisdiction. From 1010 until 1802, it was the most important political centre of Vietnam...
of Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
. At least one bridge is reported collapsed in Myanmar. In total, 390 residential homes, 14 monasteries and 9 government buildings were destroyed. In Monglin, at least 128 homes were reduced to rubble. According to the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
's population exposure data, the final damages from the earthquake are most likely to be slightly under USD $100 million.