22:55 It is official. Reuters:

Thailand has cancelled a tsunami warning in six of the country’s Andaman coast provinces that was issued after a huge earthquake struck off the coast of Indonesia, a cabinet minister said on Wednesday.

“After checking all information, we found that the situation is stable. There was a small tsunami, but there was no impact,” Information and Communication Technology Anudith Nakornthap told a televised news conference.

Indonesia earthquake

Television footage of people in Banda Aceh fleeing after an earthquake hit off the Sumatran coast Wednesday, April 11.. Pic: AP

“The situation has now returned to normal so we have lifted the warning.”

BP: Things are back to normal.

20:05 US Embassy tweets “Thai National Dept Disaster Prevention & Mitigation reports that they have downgraded the Tsunami Warning to Monitoring only”.

BP: Missed TNN interviewing Science Minister Plodrasob Surassawadee, but their summary of the interview was similar to above. Concern over the initial earthquake had passed and now they were monitoring the aftershock.

20:00 Reuters: “U.S. Pacific Tsunami Warning Center cancels tsunami watch for Indian Ocean areas”.

BP: Thailand yet to lift although now asking people to monitor the situation for now.

18:55 Reuters South eat Asia: U.S. Pacific Tsunami Warning Center says doesn’t expect “damage basin wide” across Indian Ocean.

BP: All reports are of not expecting a bad tsunami like 2004, but there are aftershocks and still situation is uncertain. Urging of caution and to monitor the situation.

18:41 MCOT (Thai TV channel) tweets “PM calls urgent meeting on tsunami risk; National Disaster Warning Centre urges public not to panic, but to be on high alert”

18:31 Reuters Southeast Asia tweets “Indonesia’s Geophysics Agency reports yet another aftershock of Aceh – this time 8.3 on Richter scale” and another tweet “Indonesia’s Geophysics Agency says detects rise in sea water level in West and North Aceh of up to 0.8 metre:

BP: Later aftershocks could also cause tsunami. Unsure if referring to the same 8.2 one below or another aftershock.

18:30 ASEAN Sec-Gen (Surin Pitsuwan) tweets “60 cm Tsunami reached Sabang, furthest tip Aceh, Sumayta. In Meulaboh, Aceh, 80 cm tsunami ! So far no damage reported !”

18:25 ThaiPBS have expert from Chula University on now who states that the risk for Thailand of a tsunami is low compared with 2004, but need two monitor the situation for aftershocks.

18:20 USGS have the aftershock listed as 8.2.

18:15 AP reports “Indonesian official says 8.1-magnitude aftershock rattles Aceh province.”

18:10 AP reports:

A massive earthquake off Indonesia’s western coast triggered a tsunami watch for countries across the Indian Ocean on Wednesday, clogging streets with traffic as residents fled to high ground in cars and on the backs of motorcycles.

Two hours after the quake hit, however, there was no sign of the feared wave. Damage also appeared to be minimal.

The U.S. Geological Survey said the 8.6-magnitude quake was centered 20 miles (33 kilometers) beneath the ocean floor around 269 miles (434 kilometers) from Aceh province.

“It wasn’t the strongest quake I’ve felt,” said 22-year-old Tuti Rahmi, while trying to reach her brother by phone from Banda Aceh, people around her crying and screaming as they poured from their homes.

“But it seemed to last forever,” she said, adding the ground shook for nearly four minutes.

The Pacific Tsunami Warning Center in Hawaii said a tsunami watch was in effect for Indonesia, India, Sri Lanka, Australia, Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, South Africa and Singapore.

But hours later, the threat appeared to have passed.

Roger Musson, seismologist at the British geological survey who has studied Sumatra’s fault lines, says the temblor was a strike-slip quake, not a thrust quake. In a strike slip quake, the earth moves horizontally rather than vertically and doesn’t displace large volumes of water.

“When I first saw this was an 8.7 near Sumatra, I was fearing the worst,” he said, noting one of the initial reported magnitudes for the quake. “But as soon as I discovered what type of earthquake it was, then I felt a lot better.”

BP: So this suggests that things are not as first feared.

18:00: USGS has downgraded the earthquake to 8.6.

Screenshot from ThaiPBS showing location of 2004 and 2012 earthquakes:

NOTE: 2555 refers to 2012: 2547 refers to 2004.

16:40: TAN Network tweets:

Water expert Dr. Seri warns of 3-4m waves hitting Phuket at 4.48pm,3-4m waves hitting Phangnga at 5pm,1-2m waves hitting Krabi at 5.58pm

BP: This will be a major test of all the warning systems implemented since the 2004 tsunami.

A 8.7 earthquake – off the west coast of northern Sumatra –  brings back memories of the 2004 earthquake and later tsunami.

From the US government Pacific Tsunami Warning Center has issued a tsunami watch which includes Thailand. BP has excerpted the relevant Thailand-specific information below
EVALUATION

EARTHQUAKES OF THIS SIZE HAVE THE POTENTIAL TO GENERATE A
WIDESPREAD DESTRUCTIVE TSUNAMI THAT CAN AFFECT COASTLINES ACROSS
THE ENTIRE INDIAN OCEAN BASIN.

 HOWEVER – IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED.  THIS
 WATCH IS BASED ONLY ON THE EARTHQUAKE EVALUATION. AUTHORITIES IN
THE REGION SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THE
POSSIBILITY OF A WIDESPREAD DESTRUCTIVE TSUNAMI.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES AT FORECAST POINTS
WITHIN THE WARNING AND WATCH AREAS ARE GIVEN BELOW. ACTUAL
ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE
LARGEST. A TSUNAMI IS A SERIES OF WAVES AND THE TIME BETWEEN
SUCCESSIVE WAVES CAN BE FIVE MINUTES TO ONE HOUR.

THAILAND         PHUKET              8.0N  98.2E    1118Z 11 APR
KO_PHRA_THONG       9.1N  98.2E    1223Z 11 APR
KO_TARUTAO          6.6N  99.6E    1256Z 11 APR

BP: More soon.