Geology of Mayotte

Mayotte is a primarily volcanic island rising steeply from the bed of the ocean to a height of 660 metres (2,170 ft) on Mont Bénara.

[2] As with other islands in the Comoros chain, Mayotte's location in the Mozambique Channel is tectonically complex, due to the displacement of the Malagasarian microcontinent from the margin of the supercontinent Gondwana.

[4] The East African Rift System became active 22 to 25 million years ago in the Miocene and its offshore extent is the youngest.

The perched aquifers are separated by units of rock that act as aquitards and aquicludes, slowing or nearly stopping the flow of water.

A set of seabed seismic recorders was put into the ocean in February 2019, for retrieval in about September of that year, which should give better locations and directional "solutions" for future events.

It was recorded by seismograms in many place including Kenya, Chile, New Zealand, Canada, and Hawaii located almost 11,000 miles (18,000 km) away.

In a discussion captured on Twitter, ideas were batted around about a partial collapse of a magma chamber roof, but at this time (2019-03) work continues to understand the event.

The earthquake swarm is now believed to have been associated with a large submarine eruption 50 km east of the island of Petite Terre, Mayotte.