Quakes strike Asia, but are they linked?
Quakes strike Asia, but are they linked?
TOKYO (Reuters): The earth moved in Asia on Thursday as powerful aftershocks rocked the west coast of Indonesia's Sumatra island, and a series of earthquakes jolted China, Myanmar and Japan.
Experts said last Sunday's quake in Indonesia's Bengkulu province, measuring 7.9 on the Richter scale, may have led to a shift in the huge tectonic plates deep under Asia's seas, prompting the burst of seismic activity this week.
Japan was rocked by three fairly strong earthquakes this week, while China and Myanmar were each hit by two. Nearly all measured above five on the open-ended Richter scale.
"It is not unusual to have a sequence of activity on a single seismic belt, some of it can be quite intense," said C.M. Tam of the Hong Kong Observatory, referring to the circum Pacific belt stretching from New Zealand across a wide swathe of East Asia.
Bengkulu's earthquake, which killed at least 120 people, injured some 1,300 and damaged thousands of homes and buildings, has spawned around 400 aftershocks, seismologists said.
The Bengkulu earthquake, which appears to have occurred after a rupture between two key plates -- the Pacific and Indian plates -- may have triggered a chain reaction of seismic activity along the circum Pacific and Eurasia belts, the seismologists said.
Professor Ding Jianhai of China's State Seismological Bureau said the Sumatra, Myanmar and China quakes all occurred along the Eurasia seismic belt stretching from the Mediterranean sea through the Himalayas to Indonesia.
He described the belt as "very active" and said he believed all the tremors were related.
"According to our estimates, there are about average 18 earthquakes at more than seven on the Richter scale globally in a year, mainly in two belts, the Euroasia belt and the belt around the Pacific," he said.
Aftershocks from the Bengkulu quake included a major tremor measuring 6.2 early on Thursday, but most experts expect the aftershocks and other regional seismic activity to wind down steadily.
An official at Japan's Meteorological Agency said Japan has experienced about 20-30 tremors since Sunday's quake in Bengkulu, although he could not say for sure if they were linked to the Sumatran earthquake.
"I think they are connected, but it is difficult to say for sure," he told Reuters.
Japan's latest tremor struck on Thursday at 9:32 a.m. (7:32 a.m. Jakarta time) on the island of Kyushu, and measured 4.9 on the Richter scale. There were no reports of damage or casualties.
On Wednesday, a tremor measuring 5.8 hit central Japan, injuring three people but causing no serious damage to buildings.
On Saturday, another earthquake measuring 5.8 swayed buildings in metropolitan Tokyo, but caused no damage.
Japan sits atop the juncture of three tectonic plates, or pieces of the earth's crust. Those three plates -- referred to by geologists as the Asian, Pacific and Philippine plates -- have been at the heart of recent seismic activity.
Katsuyuki Abe, professor at Tokyo University's Earthquake Research Institute, however, said linking quakes in Indonesia and Japan was difficult because they were so far apart.
Two earthquakes rocked Myanmar on Thursday, occurring within two hours in the remote northern Kachin state, about 1,440 km north of the capital Yangon. There were no reports of casualties.
"We think the epicenter may be at a very sparsely populated area," an official said.
About 26 minutes after Myanmar's first quake, China's southwestern province of Yunnan felt a tremor measuring 7.3, about 140 km north of the Myanmar town of Myitkyina.
An earthquake bureau official in the Yunnan district of Liuku told Reuters many buildings in the area had been damaged, although there were no immediate reports of casualties.
It was the second quake to hit China this week. On Tuesday, 24 people were injured in the northwest province of Gansu in a tremor that measured 5.9.