The 1977 Sumba earthquake (also called the Sumbawa earthquake) occurred approximately south of
Bima, Sumbawa, and beneath the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...
, at . 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 8.3, the
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, from ...
is notable for having an unusually great magnitude for a shock with a
normal faulting focal mechanism
The focal mechanism of an earthquake describes the 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 ...
.
[ The shock occurred near the southern section of the ]Sunda Trench
The Sunda Trench, earlier known as and sometimes still indicated as the Java Trench, is an oceanic trench located in the Indian Ocean near Sumatra, formed where the Australian- Capricorn plates subduct under a part of the Eurasian Plate. It is l ...
where several other tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) 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 other underwater explo ...
-generating earthquakes have occurred. The earthquake was at the time the largest outer-rise earthquake ever recorded in Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, and aftershock
In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...
s along the trench extended about eastward and westward from the epicenter.[
Although damage from the earthquake was limited to Indonesia, ground movement was reportedly felt as far afield as Albany in Australia, and the ]power supply
A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a r ...
was briefly cut in Port Hedland
A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ha ...
.[ A tsunami was generated with observed run-up heights of up to and inundation distances of up to at several locations on ]Sumba
Sumba ( id, Pulau Sumba) is an island in eastern Indonesia. It is one of the Lesser Sunda Islands and is in the province of East Nusa Tenggara. Sumba has an area of , and the population was 779,049 at the 2020 Census; the official estimate as a ...
and Sumbawa
Sumbawa is an Indonesian island, located in the middle of the Lesser Sunda Islands chain, with Lombok to the west, Flores to the east, and Sumba further to the southeast. Along with Lombok, it forms the province of West Nusa Tenggara, but there ...
.[ The combined number of victims from both the earthquake and tsunami in Indonesia was at least 107 confirmed dead and several dozen others missing, presumed dead; several sources combine the two for a total casualty figure of approximately 180 deaths and 1,100 injuries.][
]
See also
*List of earthquakes in 1977
This is a list of earthquakes in 1977. Only earthquakes of magnitude 6 or above are included, unless they result in damage and/or casualties, or are notable for some other reason. Events in remote areas will not be listed but included in statist ...
*List of earthquakes in Indonesia
__NOTOC__
This is an incomplete list of more recent recorded major earthquakes that have occurred within the boundaries of Indonesia. The determinants of the activity are indicated by the geology of the region, and the volcanic activity.
Large nu ...
*List of earthquakes in Australia
This is a list of significant earthquakes recorded in Australia and its territories. The currency used is the Australian dollar (A$) unless noted otherwise.
List of earthquakes
Other earthquakes
* Broome, 16 August 1929, magnitude 6.6, offsho ...
References
Sources
*
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External links
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{{Earthquakes in Indonesia
1977 earthquakes
Earthquakes in Indonesia
1977 tsunamis
Tsunamis in Australia
Tsunamis in Indonesia
August 1977 events in Asia