Indonesia earthquake was 376 km deep: Why was this quake different?
A powerful earthquake struck Java in Indonesia early Saturday, September 12, but unlike the shallow earthquakes that can cause severe destruction, this one originated deep beneath the Earth's surface.
The earthquake was recorded at 2:53 am IST, according to Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG). BMKG also confimred that the epicentre of the quake was in the sea, about 49 km northwest of Jakarta, at a depth of 376 km.
The magnitude of the earthquake was 6.2, according to the German Research Centre for Geosciences (GFZ).A magnitude 6.6 earthquake has just struck off the coast of Java, Indonesia, at a depth great enough that the ground typically shrugs it off.It struck approximately 115 km from Teluknaga in Banten, at a depth of roughly 359 km.Jakarta is close enough for people to feel a light pic.twitter.com/cRTGsWRCd9β SNN Finland (@snnfinalnd) September 11, 2026
There were no immediate reports of deaths or damage from the earthquake.
BMKG noted that the shaking was felt across parts of Java, including Jakarta and several areas in West Java, as well as parts of Sumatra.WHAT WAS BEHIND INDONESIA'S EARTHQUAKE?
The biggest clue to understanding the earthquake is its depth.
At 376 km below the surface, the quake is classified as a deep-focus earthquake.
Most earthquakes happen within the upper part of Earth's crust, but some occur much deeper, inside a tectonic plate that has been pushed down into the planet's interior.
Indonesia is particularly prone to such earthquakes because it lies where several tectonic plates meet. A map showing where the earthquake struck. (Photo: GFZ)
Along Java's southern side, the Indo-Australian Plate is being pushed beneath the Eurasian Plate in a process known as subduction.
As the Indo-Australian Plate sinks beneath the overriding plate, massive pressure builds up within the descending slab.
Rock can eventually fracture or suddenly shift, releasing that stored energy as seismic waves.
That is the basic mechanism behind a deep earthquake like the one recorded near Java.HOW DANGEROUS WAS INDONESIA'S EARTHQUAKE?
Depth can also make a major difference to how an earthquake is experienced at the surface.
An earthquake that begins close to the ground can send intense shaking directly into nearby communities. But seismic energy from a quake hundreds of kilometres underground has to travel through a much greater thickness of rock before reaching the surface.
By the time the waves arrive, much of their energy has spread over a wider area.
This does not mean deep earthquakes are harmless, but they can produce a different pattern of shaking from shallow earthquakes of similar magnitude.
The Java earthquake was also too deep to generate a tsunami in the way a shallow undersea earthquake can.
Tsunamis generally require a large, sudden movement of the seafloor, which is much less likely from an earthquake occurring hundreds of kilometres below it.
The earthquake therefore highlights that not all the seismic activity in Indonesia produces the same kind of danger.- EndsPublished By: Aryan Published On: Sep 12, 2026 11:22 IST
