The 2002 Sumatra earthquake occurred at 01:26 UTC on 2 November. It had a magnitude of 7.4 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pa ...

with an

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

just north of

Simeulue Simeulue is an island of Indonesia, off the west coast of Sumatra. It covers an area of 1754 square kilometres (677 square miles), including minor offshore islands. It had a population of 80,674 at the 2010 census and 92,865 at the 2020 census ...

island and caused three deaths. This

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

is regarded as a

foreshock A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full se ...

of the 2004 Indian Ocean earthquake, which had an epicenter about 60 km to the northwest.

Tectonic setting

The island of Sumatra lies on the

convergent plate boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

between the

Indo-Australian Plate The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and the surrounding ocean and extends northwest to include the Indian subcontinent and the adjacent waters. It was formed by the fusion of the Indian an ...

and the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

. The convergence between these plates is highly oblique near Sumatra, with the displacement being accommodated by near pure dip-slip faulting along the subduction zone, known as the Sunda megathrust, and near pure

strike-slip faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

along the

Great Sumatran fault The Indonesian island of Sumatra is located in a highly seismic area of the world. In addition to the subduction zone off the west coast of the island, Sumatra also has a large strike-slip fault, the Great Sumatran Fault also known as Semangko ...

. The major slip events on the subduction zone interface are typically of

megathrust Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthqu ...

type. Historically, great or giant megathrust earthquakes have been recorded in

1797 Events January–March * January 3 – The Treaty of Tripoli, a peace treaty between the United States and Ottoman Tripolitania, is signed at Algiers (''see also'' 1796). * January 7 – The parliament of the Cisalpine ...

, 1833,

1861 Statistically, this year is considered the end of the whale oil industry and (in replacement) the beginning of the petroleum oil industry. Events January–March * January 1 ** Benito Juárez captures Mexico City. ** The first stea ...

, 2004, 2005 and 2007, most of them being associated with devastating tsunamis. Smaller (but still large) megathrust events have also occurred in the small gaps between the areas that slip during the larger events, in 1935,

1984 Events January * January 1 – The Bornean Sultanate of Brunei gains full independence from the United Kingdom, having become a British protectorate in 1888. * January 7 – Brunei becomes the sixth member of the Association of Southeas ...

2000 File:2000 Events Collage.png, From left, clockwise: Protests against Bush v. Gore after the 2000 United States presidential election; Heads of state meet for the Millennium Summit; The International Space Station in its infant form as seen from S ...

and 2002.

Damage

The greatest effects were felt on the island of Simeulue, where 994 buildings were damaged, three people died and 65 were injured. The earthquake was also felt at

Tapaktuan Tapaktuan is a town in the southwest of Aceh province. The town is the capital (seat of the government) of South Aceh Regency. According to the 2013 census, it has a population of 23,100. Climate Tapaktuan has a tropical rainforest climate A ...

( VI (''Strong'')),

Meulaboh Meulaboh ( Jawoë: ملابوه; or ''Moulabouh'') is the capital of West Aceh Regency, Indonesia. Geography Meulaboh is about 245 km southeast of Banda Aceh, the capital of Aceh province. Meulaboh is located in the western part of Sumatr ...

and

Singkil Singkíl (or Sayaw sa Kasingkil) is a folk dance of the Maranao people of Lake Lanao depicting one of the episodes in the epic poem ''Darangen'', which was popularised by the Bayanihan Philippine National Folk Dance Company. Description ''S ...

(V (''Moderate'')) in the Aceh province of Sumatra.

Characteristics

The rupture area of the 2002 earthquake lies at the boundary between the rupture areas of the 2004 and 2005 earthquakes, as determined by the uplift patterns of coral

microatoll A microatoll is a circular colony of coral, dead on the top but living around the perimeter. Growth is mainly lateral, as upward growth is limited by exposure to air. Microatolls may be up to in diameter. They are named for their resemblance to ...

s. From its proximity to the epicenter of the 2004 earthquake, it is regarded as a foreshock of that event. Microatolls around Simeulue show evidence of uplift as a result of the 2002 event, distinct from the uplift caused by the 2004 event. Waveforms from this earthquake have been used to model the propagation of

Rayleigh waves Rayleigh waves are a type of surface acoustic wave that travel along the surface of solids. They can be produced in materials in many ways, such as by a localized impact or by piezo-electric transduction, and are frequently used in non-destructi ...

during the 2004 earthquake, using an empirical

Green's function In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions. This means that if \operatorname is the linear differenti ...

analysis.

References

External links

* {{Earthquakes in Indonesia 2002 disasters in Indonesia Earthquakes in Sumatra Earthquakes in Indonesia Sumatra Earthquake, 2002 November 2002 events in Asia 2002 in Indonesia History of Sumatra

Tectonic setting

Damage

Characteristics

See also

References

External links