Home Latest News EXPLAINER: Why was Indonesia’s shallow quake so lethal?

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



JAKARTA, Indonesia — A 5.6 magnitude earthquake left greater than 160 useless and a whole bunch injured as buildings crumbled and terrified residents ran for his or her lives on Indonesia’s principal island of Java.

Our bodies continued to be pulled from the particles on Tuesday morning within the hardest-hit metropolis of Cianjur, situated within the nation’s most densely populated province of West Java and a few 217 kilometers (135 miles) south of the capital, Jakarta. Quite a lot of individuals are nonetheless lacking.

Whereas the magnitude would usually be anticipated to trigger mild harm to buildings and different constructions, consultants say proximity to fault strains, the vanity of the quake and insufficient infrastructure that can’t stand up to earthquakes all contributed to the harm.

Right here’s a better have a look at the earthquake and a few explanation why it triggered a lot devastation:


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

Quakes of this measurement often don’t trigger widespread harm to well-built infrastructure. However the company factors out, “There may be not one magnitude above which harm will happen. It relies on different variables, corresponding to the gap from the earthquake, what kind of soil you’re on, constructing development” and different components.

Dozens of buildings had been broken in Indonesia, together with Islamic boarding colleges, a hospital and different public services. Additionally broken had been roads and bridges, and components of the area skilled energy blackouts.


Specialists stated proximity to fault strains, the depth of the temblor and buildings not being constructed utilizing earthquake-proof strategies had been components within the devastation.

“Though the earthquake was medium-sized, it (was) near the floor … and situated inland, near the place folks reside,” stated Gayatri Marliyani, an assistant geology professor at Universitas Gadjah Mada, in Yogyakarta, Indonesia. “The power was nonetheless massive sufficient to trigger important shaking that led to wreck.”

The worst-affected space is near a number of identified faults, stated Marliyani.

A fault is a spot with a protracted break within the rock that kinds the floor of the earth. When an earthquake happens on one among these faults, the rock on one aspect of the fault slips with respect to the opposite.

“The realm most likely has probably the most inland faults in comparison with the opposite components of Java,” stated Marliyani.

She added that whereas some well-known faults are within the space, there are numerous different lively faults that aren’t effectively studied.

Many buildings within the area are additionally not constructed with quake-proof designs, which additional contributed to the harm, stated Danny Hilman Natawidjaja, an earthquake geology professional on the Indonesian Institute of Sciences Geotechnology Analysis Middle.

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


The nation of greater than 270 million folks is continuously struck by earthquakes, volcanic eruptions and tsunamis due to its location on the arc of volcanoes and fault strains 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 world’s earthquakes happen.

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

In February, a magnitude 6.2 earthquake killed a minimum of 25 folks and injured greater than 460 in West Sumatra province. In January 2021, a magnitude 6.2 earthquake killed greater than 100 folks and injured almost 6,500 in West Sulawesi province.

A robust Indian Ocean quake and tsunami in 2004 killed 230,000 folks in a dozen international locations, most of them in Indonesia.

The Related Press Well being and Science Division receives assist from the Howard Hughes Medical Institute’s Division of Science Schooling. The AP is solely liable for all content material.

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