Earthquake rattles two regencies in Bali

Wahyoe Boediwardhana, The Jakarta Post, Bali

Bali was jolted by a magnitude 5.0 Richter scale tectonic earthquake on Tuesday, with residents in Amlapura, Karangasem regency and parts of Klungkung regency saying the rumbling went on for about three minutes.

According to an official at the Denpasar Meteorology and Geophysics Agency (BMG), Nyoman Sulastra, "the epicenter of the quake was located about 40 kilometers northeast of Amlapura".

The epicenter was reportedly located in the Lombok strait, about 16 km undersea. Residents in the two areas claimed they had felt the tremors four times.

The intensity of the series of aftershocks recorded by the seismograph varied between 2 to 3 magnitude on the Richter Scale.

"No casualties or material losses were reported, but people were overcome by panic. At the Karangasem police station, for instance, people were seen fleeing from building," said Bali police spokesman Sr. Comr. A.S. Reniban.

The quake was not noticed in the capital, Denpasar, which is about 40 km from Klungkung.

Some local residents said they feared that Mount Agung could erupt, but according to the BMG, the tremors that were felt for several minutes were due to the movement of the Indo-Australia tectonic plates depressing the Euro-Asia plate, and so did not affect Mount Agung.

The plate which runs parallel to the western coast of Sumatra, and continues down along the western edge of the Indonesian archipelago, is said to be shifting each day in varying degrees, but is classified as "very inert" as the movement is about seven to 12 millimeters annually.

"The tectonic plate movement means the southern part of Java, Bali, West Nusa Tenggara and East Nusa Tenggara will remain prone to earthquakes," said Sulastra.

The BMG's seismograph located in Kuta, records six to 10 tremors per day, generally below magnitude 4, with a depth of more than 80 km under the sea.

Due to the depth of the epicenter, only weak vibrations were felt on the surface usually.

Karangasem regency was previously hit by a 6.1-magnitude quake in January, 2004, destroying over 4,000 homes.

"We have determined that the area is an active fault area where a displacement can occur anytime," said Sulastra.

He declined to predict the other areas where earthquakes might occur due to the agency's lack of ability, and only said that the area had been established as an active fault area.