Twin earthquakes rattle Indonesia's Sumatra: USGS

Two powerful quakes struck Indonesia's Sumatra on Sunday, US seismologists said, but no tsunami warning was issued and there were no immediate reports of damage or casualties.
Channel NewsAsia 8 Nov 15;

PADANG: Two powerful quakes struck Indonesia's Sumatra on Sunday (Nov 8), US seismologists said, but no tsunami warning was issued and there were no immediate reports of damage or casualties.

An initial 6.1-magnitude undersea tremor struck at a depth of 75 kilometres in the afternoon, the US Geological Survey (USGS) said. It was followed around seven hours later by a strong 6.4-magnitude quake, also at sea, at a depth of 7.7 kilometres, USGS reported.

The first quake struck 111 kilometres south of the city of Sibolga, in North Sumatra province, while the epicentre of the second was a similar distance from Sabang, an islet off the northernmost tip of Sumatra. Smaller tremors were recorded throughout the afternoon and evening.

Mochammad Riyadi, a senior official from Indonesia's meteorology, climatology and geophysics agency, said the first quake was felt strongly for 15 seconds in Mandailing Natal district, which is around 85 kilometres from the quake's epicentre.

"Moderate tremors" were also felt in Padang, the capital of West Sumatra, he said. "We have no reports of damage or casualty so far. No tsunami alert was issued," he added.

An AFP correspondent in Padang said "the earth swayed back and forth for around 10 seconds", but the majority of residents remained calm.

Indonesia sits on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent seismic and volcanic activity.

- AFP/al/de


Tsunamis may be generated after large earthquake strikes Indonesia: NEA
AsiaOne 8 Nov 15;

SINGAPORE - An earthquake measuring 6.5 on the Richter scale has been detected on the western side of Sumatra, Indonesia on Sunday (Nov 8) at 5.34pm, the National Environment Agency (NEA) said in a push alert notification.

Describing the earthquake as 'large', NEA said that the epicentre is located 559km west from Singapore, and warned that tsunamis may be generated near the epicentre.

No tremors were reported. "Singapore is unlikely to be affected," NEA added.

Padang, the capital of west Sumatra, is the nearest major city to the earthquake epicentre which lies 231km away.

The United Stated Geological Survey said that the quake was 75.1km deep.


6.0-magnitude quake rocks North Sumatra`s Mandaling Natal
Antara 8 Nov 15;

Medan, N Sumatra (ANTARA News) - An earthquake measuring 6.0 on the Richter scale rocked Mandailing Natal district, North Sumatra, on Sunday evening.

The epicenter of the earthquake which struck at 04.34 p.m. local time was located 85 km southwest of Mandailing Natal at a depth of 86 km, according to the Meteorology, Climatology and Geophysics Agency (BMKG) office in Medan, capital of North Sumatra province.

The earthquake was strongly felt in the district, prompting local residents to stay outdoors to avoid undesired things, spokesman for the Mandailing Natal District Disaster Mitigation Board (BPBD) Supardi Lubis said.

There is no immediate report of casualties and material damage.

Reported by Irwan Arfa