The United States Geological Survey
recorded a Magnitude 4.7 Earthquake at a
depth of 10.0 km, roughly 7 km to the southwest of Petite Terre Island in the Mayotte Archipelago, an overseas Department of
France in the Mozambique Channel between the Comoros Islands and
Madagascar,
slightly before 4.15 am local
time (slightly before 7.15 am GMT) on Saturday 9 February 2019. There are no reports of any damage or casualties
associated with this event, but it may have been felt locally.
The approximate location of the 9 February 2019 Mayotte Earthquake. USGS.
Geologically Mayotte forms the oldest part of the Comoros Island Chain, which are hotspot
volcanoes, located over a magma plume which originated deep in
the Earth's mantle which is rising through the overlying African Plate,
though they may be connected to the East African Rift Zone, which
extends from the Red Sea to the coast of Mozambique, roughly a thousand
kilometres southwest of the Comoros. Volcanism is thought to have first
started beneath what is now Mayotte about 15 000 years ago, and
persisted until about 5000 years ago, with the islands rising above
sealevel about 7000 years ago, and continuing to grow after the
cessation of volcanism due to the accretion of Coral reefs. Although all
volcanic activity on the islands ceased thousands of years ago, the
islands are still subject to occasional seismic events (Earthquakes),
associated with the movement of magma deep beneath the hotspot. These
can be potentially hazardous, due to the nature of the rock which makes
up the island, mostly poorly consolidated volcanic ash, which is prone
to liquefaction when sufficiently shaken; a Magnitude 5.0 Earthquake in
1993 is thought to have caused about €1.7 million in damage, mostly to
privately owned homes.
Witness
accounts of Earthquakes can help geologists to understand these events,
and the structures that cause them. The international non-profit
organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.
See also...
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