The United States Geological Survey recorded a Magnitude 6.3 Earthquake at a depth of 14 km beneath the island of Palau Alor, at the eastern end of the Lesser Sunda Islands, slightly before 11.45 am local time (slightly before 3.45 am GMT) on Wednesday 4 November 2015. There are no reports of any damage or casualties arising from this event, though people have reported feeling it on Palau Alor and East Timor.
The approximate location of the 4 November 2015 Palau Alor Earthquake. Google Maps.
The Lesser Sunda Islands are located on the northern part of the Timor Microplate. This is trapped between the converging Eurasian and Australian Plates, both of which are being subducted beneath it. This is not a smooth process; the two subducting plates continuously stick to the overlying plate, then break away as the pressure builds up, causing Earthquakes in the process. In the south the Australian Plate is passing under the island of Timor, with material from the subducted plate melted by the friction and the heat of the Earth's interior rising through the Timor Plate to feed the volcanoes of the island. In the north the Eurasian Plate is being subducted in the same way, feeding the volcanoes there.
The subduction zones beneath the Timor Microplate. Hamson (2004).
Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organization 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.
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