At least 53 dead following Magnitude 7.7 Earthquake off the coast of Flores Island, Indonesia.

The Indonesian Meteorological, Climatological, and Geophysical Agency recorded a Magnitude 7.7 Earthquake at a depth of about 15 km, to the north of the Island of Flores in East Nusa Tenggara Province, Indonesia slightly before 5.00 am on Saturday 15 August 2026, Eastern Indonesian Time (slightly before 10.00 pm on Friday 14 August, GMT). The Earthquake was felt as far away as Bali, and caused a tsunami as high as 1.6 m on some parts of the coast of Flores. The initial event has been followed by more than three hundred aftershocks.

The approximate location of the 15 August 2026 Flores Earthquake. USGS.

At least 53 people have died as a result of this event, the majority of them killed in their sleep as buildings collapsed onto them, making this the most deadly Earthquake to hit Indonesia since 2022. A further 135 people are known to have been injured, with more than 5000 people displaced and over 1900 homes damaged or destroyed. The Earthquake also caused damage to at least 93 educational facilities, 36 health facilities, 38 government offices, and five places of worship. A maritime passenger terminal collapsed in Maumere on the north coast of Flores.

Damaged and collapsed building in the city of Mbay on the north coast of Flores. Ignasius Kunda/EPA.

Flores is one of the Lesser Sunda Islands, which 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. In the south the Australian Plate is passing under the island of Timor, while in the north the Eurasian Plate is being subducted in the same way. This is not a smooth process; the rocks of the various plates constantly stick together, only to break apart again as the pressure builds up, causing Earthquakes in the process.

The subduction zones beneath the Timor Microplate. Hamson (2004).

Earthquakes along subductive margins are particularly prone to causing tsunamis, since these often occur when the overlying plate has stuck to the underlying plate, being pulled out of shape by its movement. Eventually the pressure builds up too far and the overlying plate snaps back, causing an Earthquake and a tsunami. 

Simplified graphic showing tsunami generation along a convergent margin, and how this can be monitored using ground-based GPS systems to give early warnings of the arrival of tsunamis. NASA/JPL/CalTech.

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