The 1935 Sumatra earthquake occurred at on 28 December. It had a magnitude of 7.7 and a maximum felt intensity of VII (''Damaging'') on the

European macroseismic scale The European Macroseismic Scale (EMS) is the basis for evaluation of seismic intensity in European countries and is also used in a number of countries outside Europe. Issued in 1998 as an update of the test version from 1992, the scale is referred ...

. It triggered a minor

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

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 and the Eurasian plate. 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 The Sunda megathrust is a fault that extends approximately 5,500 km (3300 mi) from Myanmar (Burma) in the north, running along the southwestern side of Sumatra, to the south of Java and Bali before terminating near Australia. It is cap ...

, and near pure

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

along the

Great Sumatran fault The Great Sumatran fault, also known as Semangko fault, is a large strike-slip fault running the entire length of the island of Sumatra. This Indonesian island is located in a highly seismic area of the world, including a subduction zone off th ...

. 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 Repu ...

1833 Events January–March * January 3 – The United Kingdom reasserts British sovereignty over the Falkland Islands in the South Atlantic Ocean. * February 6 (January 25 on the Greek calendar) – Prince Otto Friedrich Ludwig of Bavaria arr ...

1861 This year saw significant progress in the Unification of Italy, the outbreak of the American Civil War, and the emancipation reform abolishing serfdom in the Russian Empire. Events January * January 1 ** Benito Juárez captures Mexico Ci ...

2004 2004 was designated as an International Year of Rice by the United Nations, and the International Year to Commemorate the Struggle Against Slavery and Its Abolition (by UNESCO). Events January * January 3 – Flash Airlines Flight 60 ...

2005 2005 was designated as the International Year for Sport and Physical Education and the International Year of Microcredit. The beginning of 2005 also marked the end of the International Decade of the World's Indigenous Peoples, Internationa ...

and

2007 2007 was designated as the International Heliophysical Year and the International Polar Year. Events January * January 1 **Bulgaria and Romania 2007 enlargement of the European Union, join the European Union, while Slovenia joins the Eur ...

, 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 2000 was designated as the International Year for the Culture of Peace and the World Mathematics, Mathematical Year. Popular culture holds the year 2000 as the first year of the 21st century and the 3rd millennium, because of a tende ...

and

2002 The effects of the September 11 attacks of the previous year had a significant impact on the affairs of 2002. The war on terror was a major political focus. Without settled international law, several nations engaged in anti-terror operation ...

Damage

The Batu Islands and the neighbouring coast of

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

were the most affected areas. The lighthouse on Bodjo island was damaged and cracks appeared in the hill that it stands on. Several houses were destroyed at Pulu Tello. The islands of Tanahbala and Sigata showed evidence of uplift, with low-lying areas no longer flooded at high tide. Near

Padang Padang () is the Capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of West Sumatra. It had a population of 833,562 at the 2010 CensusBiro Pusat Statistik, Jakarta, 2011. and 909,040 at the 2020 Census;Bad ...

power and telephone lines swayed, with some lines being cut. Some huts collapsed at

Sibolga Sibolga (formerly sometimes Siboga) is a city and a port located in the natural harbour of Sibolga Bay on the west coast of North Sumatra province, in Indonesia. The city is located on the western side of North Sumatra facing the Indian Ocean, ...

, although there were no reported casualties.

Characteristics

The earthquake is thought to have occurred on the plate interface at a depth of about 28 km. The estimated source parameters for the earthquake are 65 km length, 30 km width with a maximum displacement of 3 m. Such a rupture zone has a predicted pattern of uplift and subsidence and this has been found to be consistent with paleogeodetic records taken from coral microatolls around the Batu Islands.

References

External links

* {{DEFAULTSORT:1935 Sumatra Earthquake Earthquakes in Sumatra Sumatra Earthquake, 1935 Earthquakes in Indonesia Sumatra Earthquake Sumatra Earthquake 20th century in Sumatra 1935 disasters in Asia 1935 disasters in Oceania 20th-century disasters in Indonesia

Tectonic setting

Damage

Characteristics

See also

References

External links