BANGKOK — A powerful earthquake struck Indonesia’s main island of Java on Monday, killing at least 162 people, injuring hundreds more and shaking tall buildings in the capital, Jakarta, 60 miles away. Many people were believed to be still trapped beneath the rubble, leading to fears that the death toll would sharply increase.
The magnitude 5.6 earthquake — which struck near the city of Cianjur, one of the most disaster-prone districts in Indonesia — caused the collapse of hundreds of buildings and triggered landslides that prevented many people from reaching the city’s main hospital.
Emergency workers and others scrambled overnight to find people trapped in the debris. But rescue efforts were hampered because the hospital itself was damaged and had lost electrical power, said Herman Suherman, a government official in Cianjur.
“This is overwhelming,” Mr. Suherman said, adding that the hospital was desperate for more doctors to treat the flood of injuries and for a restoration of power. He said that many people, unable to reach the main hospital, were being treated wherever they were injured.
As evening fell, Ridwan Kamil, West Java’s governor, said 162 people had died, but the police in Cianjur said that the number of fatalities was likely to increase as rescuers reached those trapped.
“So many buildings crumbled and shattered,” Mr. Ridwan Kamil said. “There are residents trapped in isolated places, so we are under the assumption that the number of injured and deaths will rise with time.”
Particularly worrisome was that Monday’s quake was very shallow, occurring at a depth of only six miles, according to the United States Geological Survey. Shallow quakes can often be more destructive than deeper ones because the seismic waves travel a shorter distance to the surface, losing less energy along the way.
Survivors of the quake, sometimes using just their hands, dug well into the night in search of signs of life. A television video showed rescuers unable to reach victims because they lacked the tools to dig and remove debris.
Emergency workers were treating the injured on stretchers outside the main hospital and in parking lots and open spaces. Many, including children, were given oxygen masks and were receiving intravenous treatment.
The government erected tents outside the damaged hospital to shelter and treat those who were injured. Many arrived on the backs of motorbikes because ambulances and other vehicles could not navigate landslides that blocked some roads.
As more victims arrived, emergency workers were prioritizing those who needed immediate treatment. Both the hospital and the surrounding tent areas were filled to capacity, said Mr. Ridwan Kamil, adding that many family members had become separated by the quake. A number of the injured complained of pain in their shoulders and ribs from being hit by falling debris.
In Jakarta, residents reported that buildings swayed and furniture was shaken, causing people to run into the streets for safety.
According to early reports from the Indonesian National Disaster Mitigation Agency, the earthquake destroyed 343 buildings and damaged many others, including some government offices, schools and religious houses.
The vast Indonesian archipelago, with its long coastline and many islands, lies on the “Ring of Fire,” an arc of volcanoes and fault lines along the Pacific Basin, that is frequently hit by earthquakes and volcanic eruptions. Large and small earthquakes occur virtually every day.
The U.S. Geological Survey said Monday’s quake occurred in a subduction zone, an area where one of the planet’s large crustal plates, in this case the Australian, is sliding beneath another, the Sundan. The process is very slow — the two plates are moving with respect to each other at a rate of two inches a year. But as in all subduction zones around the world, the movement builds frictional stresses between the two plates that result in frequent earthquakes.
In the past 15 years there have been four quakes of magnitude 6.5 or larger in the subduction zone within 150 miles of Monday’s earthquake, the survey said. The largest was in 2007, which at magnitude 7.5 released 700 times the energy of Monday’s quake. But it occurred at a depth of 175 miles, and there were no reports of damage or injuries.
Monday’s quake was the latest in a series of recent disasters that have befallen Indonesia. In February, a magnitude 6.2 earthquake killed at least 25 people and injured more that 450 others in West Sumatra province. In January 2021 a magnitude 6.2 earthquake killed more than 100 people and injured nearly 6,500 people in West Sulawesi province.
The Cianjur district is one of the most dangerous areas in Indonesia, suffering frequent floods, landslides and droughts as well as earthquakes, tsunamis and volcanic eruptions, according to the Indonesia Disaster Risk Index.
In the most devastating disaster in recent years, a powerful Indian Ocean earthquake off Sumatra island in northern Indonesia caused a tsunami in December 2004 that killed nearly 230,000 people, more than half of them in Indonesia.
In 1883 the Krakatoa volcano in the Sunda Strait was the deadliest and most destructive volcanic events in recorded history. The explosion was heard hundreds of miles away and a filter of ash colored sunsets around the world. At least 36,000 deaths were attributed to the eruption and the tsunami that followed it.
Since then a new type of volcano, known as “Baby Krakatoa,” has begun to rise in its place.
Death tolls continue to increase from such disasters as Indonesia’s population has risen rapidly to 270 million, as cities have expanded and people have made their homes in ever more precarious areas, said Kerry Sieh, an American seismologist who closely follows Indonesia.
Henry Fountain contributed reporting.
Dera Menra Sijabat contributed reporting.