The 1843 Nias earthquake off the northern 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 sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

, Indonesia caused severe damage when it triggered a tsunami along the coastline. The earthquake with a

moment magnitude 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 pape ...

() of 7.8 lasted nine minutes, collapsing many homes in Sumatra and

Nias Nias ( id, Pulau Nias, Nias language: ''Tanö Niha'') (sometimes called Little Sumatra in English) is an island located off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago () of which the island is the centre, ...

. It was assigned a maximum

modified Mercalli intensity The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...

of XI (''Extreme'').

Tectonic setting

The west coast of Sumatra is dominated by the

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

; a 5,000 km long convergent boundary where the

Australian Plate The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when India broke ...

subducts beneath the

Burma Plate The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate. This island arc ...

and

Sunda Plate The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements have ...

at a rate of 60 mm/yr. Convergence along this plate boundary is highly oblique, severely deforming the overriding Sunda Plate, where it is accommodated by the strike-slip motion 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, subduction zone off the west coast of the island, Sumatra also has a large Fault (geology)#Strike-slip faults, strike-slip fault, th ...

. Dip-slip fault can rupture within the downgoing Australian Plate at deep depths as well; the 2009 magnitude 7.6 earthquake near

Padang Padang () is the capital and largest city of the Indonesian province of West Sumatra. With a Census population of 1,015,000 as of 2022, it is the 16th most populous city in Indonesia and the most populous city on the west coast of Sumatra. Th ...

was caused by reverse faulting at a depth of 80 km. The subduction zone offshore Sumatra has been responsible for several large earthquakes in

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 6 ...

and

2005 File:2005 Events Collage V2.png, From top left, clockwise: Hurricane Katrina in the Gulf of Mexico; the Funeral of Pope John Paul II is held in Vatican City; "Me at the zoo", the first video ever to be uploaded to YouTube; Eris was discovered in ...

. Occasionally, the subduction ruptures in earthquake that reaches the trench, triggering large tsunamis such as in

1907 Events January * January 14 – 1907 Kingston earthquake: A 6.5 Mw earthquake in Kingston, Jamaica, kills between 800 and 1,000. February * February 11 – The French warship ''Jean Bart'' sinks off the coast of Morocco. ...

, 2004 and

2010 File:2010 Events Collage New.png, From top left, clockwise: The 2010 Chile earthquake was one of the strongest recorded in history; The Eruption of Eyjafjallajökull in Iceland disrupts air travel in Europe; A scene from the opening ceremony of ...

Impact

The earthquake's destructive effects were felt on Nias and Sumatra islands. Shaking was described as weak and oscillating, but rapidly intensified. The extreme shaking was felt for up to nine minutes. It was so violent that standing or walking was impossible. Stone buildings and a fortress on a hill at

Gunungsitoli Gunungsitoli is a city located in North Sumatra province, Indonesia, on the Indian Ocean island of Nias, west of Sumatra. Gunungsitoli is the island's only city and is the main hub for the island and surrounding smaller islands. Located on the n ...

on Nias Island were destroyed. Trees were uprooted and snapped. Cracks appeared in the ground and mud erupted from within.

Liquefaction In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the ...

on Nias island caused some buildings to sink into the ground. Homes collapsed, killing many residents. Government offices and a Commandant's house were destroyed. Small

landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...

s also occurred. Shaking was also felt in

Penang Island Penang Island ( ms, Pulau Pinang; zh, 檳榔嶼; ta, பினாங்கு தீவு) is part of the state of Penang, on the west coast of Peninsular Malaysia. It was named Prince of Wales Island when it was occupied by the British Ea ...

and Singapore. In Singapore, tremors were felt at half past midnight on January 6. Shaking was felt stronger on the hills, described as oscillating in an east–west direction. At Penang Island, shaking was felt in a north–south direction.

Aftershocks

Many aftershocks were felt until 04:30 local time. Earthquakes were felt every two minutes of each other. Another earthquake was felt on January 8 at 14:30.

Tsunami

The first tsunami waves were reported at 00:30 local time, causing extreme damage. It arrived from the southeast and struck the island. Cattle and human residents were swept away by the waves. At the villages of

Barus Barus is a town and ''kecamatan'' (district) in Central Tapanuli Regency, North Sumatra Province, Sumatra, Indonesia. Historically, Barus was well known as a port town or kingdom on the western coast of Sumatra where it was a regional trade center ...

(on Sumatra) and Palan Nias (on Nias Island), large waves were reported over a period of two days. A large tsunami reportedly destroyed settlements on the east coast of Nias and Sumatra islands. The tsunami wiped out a large village located two kilometers from Gunungsitoli.

Proa Proas are various types of multi-hull outrigger sailboats of the Austronesian peoples. The terms were used for native Austronesian ships in European records during the Colonial era indiscriminately, and thus can confusingly refer to the do ...

s located on a nearby river were washed inland by up to 50 meters. Many people were killed by the tsunami and earthquake. Ships at Barus were dumped 600 meters inland due to the tsunami. The bodies tsunami victims were found along the shores in the days following. Kampong Mego, a large village on the island, was totally destroyed. The waves also smashed prows at the coast in the village of Goenong Sie Foli, north of Mego. The tsunami persisted until 04:30. A sea disturbance was observed in the

Malacca Strait The Strait of Malacca is a narrow stretch of water, 500 mi (800 km) long and from 40 to 155 mi (65–250 km) wide, between the Malay Peninsula (Peninsular Malaysia) to the northeast and the Indonesian island of Sumatra to the southwest, conne ...

at the time of the earthquake, however, that was attributed to the weather.

Characteristic

A research article published in 2006 by the journal ''Science of Tsunami Hazards'' estimated the

() at 7.2. In the book ''A catalogue of tsunamis on the western shore of the Pacific Ocean'', the

surface-wave magnitude The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This ma ...

was assigned 7.3. In 2013, the journal ''

Geophysical Research Letters ''Geophysical Research Letters'' is a biweekly peer-reviewed scientific journal of geoscience published by the American Geophysical Union that was established in 1974. The editor-in-chief is Harihar Rajaram. Aims and scope The journal aims for ra ...

'' published a finding that re-estimated the moment magnitude to at least 7.8 based on information of the extent of tsunami inundation. It is unclear where the source of the earthquake originated, but may have occurred on the interface of the Sunda megathrust or a shallow

splay fault Splay may refer to: *Splay, a verb meaning slant, slope or spread outwards *Splay (physiology), the difference between urine threshold and saturation *Splay (Japanese band), a J-pop band from Osaka *Splay Networks, a Sweden-headquartered group of ...

within the

accretionary wedge An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the do ...

of the overriding plate. The events of 1843 is the earliest record of an earthquake on Nias Island. Subsequent earthquakes in 1861 and 1907 would also occur on the island. It resulted in some uplift and subsidence on the northwestern section of Nias Island as investigated by scientists using

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. The island was raised by 17 centimeters during the quake. Uplift of the island also occurred during the large earthquakes of 1861, 2005 and

References