EXPLAINER: Why was Indonesia’s shallow quake so deadly?


JAKARTA, Indonesia — A 5.6 magnitude earthquake left greater than 260 lifeless and loads injured as structures crumbled and terrified citizens ran for his or her lives on Indonesia’s primary island of Java.

Our bodies endured to be pulled from the particles on Tuesday within the hardest-hit town of Cianjur, within the nation’s maximum densely populated province of West Java and a few 217 kilometers (135 miles) south of the capital, Jakarta. Plenty of persons are nonetheless lacking.

Whilst the magnitude would in most cases be anticipated to purpose mild harm to structures and different buildings, mavens say proximity to fault traces, the vanity of the quake and insufficient infrastructure that can not resist earthquakes all contributed to the wear and tear.

Right here’s a more in-depth have a look at the earthquake and a few the reason why it led to such a lot devastation:


The U.S. Geological Survey stated the quake overdue Monday afternoon measured 5.6 magnitude and struck at a intensity of 10 kilometers (6.2 miles).

Quakes of this measurement generally don’t purpose well-liked harm to well-built infrastructure. However the company issues out, “There isn’t one magnitude above which harm will happen. It is determined by different variables, equivalent to the gap from the earthquake, what form of soil you’re on, development development” and different components.

Dozens of structures have been broken in Indonesia, together with Islamic boarding colleges, a health facility and different public amenities. Additionally broken have been roads and bridges, and portions of the area skilled energy blackouts.


Mavens stated proximity to fault traces, the intensity of the temblor and structures no longer being built the usage of earthquake-proof strategies have been components within the devastation.

“Even if the earthquake was once medium-sized, it (was once) with reference to the skin … and positioned inland, with reference to the place other folks are living,” stated Gayatri Marliyani, an assistant geology professor at Universitas Gadjah Mada, in Yogyakarta, Indonesia. “The power was once nonetheless big enough to purpose important shaking that led to break.”

The worst-affected house is with reference to a number of recognized faults, stated Marliyani.

A fault is a spot with a protracted spoil within the rock that bureaucracy the skin of the earth. When an earthquake happens on this kind of faults, the rock on one aspect of the fault slips with appreciate to the opposite.

“The realm more than likely has probably the most inland faults in comparison to the opposite portions of Java,” stated Marliyani.

She added that whilst some well known faults are within the house, there are lots of different energetic faults that don’t seem to be effectively studied.

Many structures within the area also are no longer constructed with quake-proof designs, which additional contributed to the wear and tear, stated Danny Hilman Natawidjaja, an earthquake geology skilled on the Indonesian Institute of Sciences Geotechnology Analysis Middle.

“This makes a quake of this measurement and intensity much more damaging,” he stated.


The rustic of greater than 270 million other folks is steadily struck by way of earthquakes, volcanic eruptions and tsunamis as a result of its location at the arc of volcanoes and fault traces within the Pacific Basin referred to as the “Ring of Fireplace.” The realm spans some 40,000 kilometers (25,000 miles) and is the place a majority of the sector’s earthquakes happen.

A lot of Indonesia’s earthquakes are minor and purpose little to no harm. However there have additionally been fatal earthquakes.

In February, a magnitude 6.2 earthquake killed no less than 25 other folks and injured greater than 460 in West Sumatra province. In January 2021, a magnitude 6.2 earthquake killed greater than 100 other folks and injured just about 6,500 in West Sulawesi province.

A formidable Indian Ocean quake and tsunami in 2004 killed 230,000 other folks in a dozen nations, maximum of them in Indonesia.

The Related Press Well being and Science Division receives enhance from the Howard Hughes Scientific Institute’s Division of Science Schooling. The AP is simply answerable for all content material.

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