Massive 7+ earthquakes near Vanuatu Efate Island (August 20/21, 2011

Earthquake overview : A massive earthquake measuring 7.5 magnitude struck the Vanuatu area at 3:55 AM in the night. A tsunami with theoretical waves up to 1.9 meters could be expected on a Vanuatu island (see below).
Read also : Vanuatu massive earthquakes and aftershocks : impressive "experience" reports

Earthquake-Report.com has made a short video on this earthquake. For those who do not like to read a lot, this is the perfect way of being informed. The video is also embedded at the bottom of the page.
http://www.youtube.com/user/quakesos?feature=mhee#p/a/u/0/dQEHLKOxrEo

Port Vila Vanuatu - Panoramio image courtesy GlenCraig - http://www.panoramio.com/photo/8784222

27/08 - 22:47 UTC : M 5.2      2011/08/27 12:07     Depth 53.0 km     VANUATU - Aftershock
11:07:35 PM at epicenter
Aftershock very close to Efate's Port-Vila.
Based on the reports we are receiving from people living in Port-Vila, this aftershock did more than all the other aftershocks which epicenter's were mostly at a greater distance from Efate.
47 km (29 miles) S (179°) from PORT-VILA, Vanuatu
Satellite map of the greater epicenter area
Aftershock Felt Reports :
Port-Vila : its just pretty scary.I only moved here 1 week ago just as the big one hit on 20.8.11 and we've been having small ones ever since. The one just now about 11.10pm was almost as big as last saturdays i think - MMI VII
Port-Vila : Just had another house rattling jolt here in Port Vila, Vanuatu. Sat PM around 11;15pm local time. Probably around 6 on the scale. August has been a busy earthquake month again for us this year with several noticeable quakes this time last year as well. I live outside of Port Vila on a small bay. It is very quiet and I hear the earthquakes coming. They sound like are very large cattle truck coming down the road and they always have a distinct sound that separates them from a general traffic type of noise. A few things fell over but no damage. Our house was bought in from NZ and is made of timber. It usually sways but not visible damage once again. Steve - MMI V
Port-Vila : We had a 5.2 shake around 11pm.  Was quite intense, kitchen sounded like it was going to explode with glassware rattling for what seemed like several seconds. Felt like something had picked up the place and was giving it a good shaking. Thankfully didn't last long! Just noticed this morning that the rubber is starting to come out from around my bedroom window.

Mainshock FELT Reports as received by Earthquake-Report.com from Vanuatu (please continue sending them)

Port Vila, Efate, Vanuatu : Report from Margarette Cantwell living in Port Vila : We were woken at 3.55 Sunday morning with a quite large quake which rattled the windows of my apartment. I'm on the 2nd and 3rd story of a motel built in the 1970's. After another couple of quakes we then got the 5.30 one which according to the smaller than the first one. It certainly didn't feel smaller and it seemed to last longer. I was in the bathroom, where i sat down on the floor and held onto the towel rail while everything seemed to be moving around me. Just resulted in light stuff falling from shelves and no damage to my place.
Other friends reported glasses broken and things falling over.
I heard also that there was a landslide on the road to the main wharf, but haven't heard of any other damage. There was a tsunami warning for a short time and some locals moved to higher ground and theres just ignored it.
We are still getting some small quakes, I was woken again this morn at 3.45 and had 2 more before I got up.
Vanuatu : Longues secousses. Piscine qui deborde. Long shaking + swimming pool which is overflowing. MMI V and MMI VI checked.
Efate : Experienced severe quake at 5.30 approx - much stronger than 7.5 at 3.55 am  MMI VIII checked (Severe shaking)
Port Olry, Espiritu Santo, Vanuatu : approx. 350 km from the epicenter : Weak shaking indicated
Port Vila, Efate, Vanuatu : Yesterday's earthquake (21/08/11) - I am suprised that the magnitude was as little as it was.  It was very strong and very scarey. Had people running for high ground.  As written, impossible to get detailed information at the time, and on arrival back in NZ later that day, alot of differing information.
No tidal waves or surges seen in Erakor Bay, but very unsettled water before and after the biggest shake at around 0515 (local time - GMT +11). MMI VI, Strong shaking indicated.

21/08 - 23:05 UTC : People in Port Vila have really shaken up by the earthquake but there is minimal damage. The Vanuatu press must have been all outside Vanuatu as almost nobody reported on Monday morning about this earthquake!

21/08 - 09:47 UTC : Some minor damage was reported in the southern part of the country and in the surrounding areas of Port-Vila, said an official with Vanuatu’s National Disaster Management Office. (Source : Washington Post). The precise kind,  extend and sources of the damage (shaking or/and tsunami) was not specified (ER).

21/08 - 08:30 UTC : Remark from the Founder of Earthquake-Report.com

It frustrates Earthquake-Report.com that not one single source on the internet is telling the world what really happened on Efate. Except to the kind person who did send us the above Felt report and a general remark here and there that no damage has been recorded, we cannot find any other report at this moment.  We do see regularly Vanuatu people coming to read our article  (we see only the flag and where they are from and ...  a lot of them are from Port Vila, Efate). These people should know that obtaining direct information from Vanuatu is almost like getting information from outer space. As they are really living in one of the most dangerous places of our planet, a smooth and direct link to the outside world would also be very important for them. We would appreciate it very much if they would share what they know with our worldwide reader base.  With more than thousand reliable earthquake related sources in our database, Vanuatu and some other countries in the world are like  holes in our news network. We would appreciate it very much if a couple of Vanuatu citizens would contact us in case of a dangerous earthquake. You can use the form below to let us know.
Armand Vervaeck

22:30 UTC : The normally 'well informed' Radio New Zealand International reports that the Vanuatu National Disaster Management Office says it has received no reports of damage and has canceled a local tsunami warning advisory.

21:29 UTC : The Vanuatu Tsunami Warning Center has canceled all tsunami warnings after a 7.0-magnitude earthquake struck off its coast, generating local tsunami waves but no damage.

21:02 UTC : The area has been shaken over and over again by the many, sometimes massive, strong and very stron aftershocks.  At the time of writing, this were the most powerful aftershocks so far :
M 4.9      2011/08/20 20:13     Depth 48.9 km      VANUATU
M 5.0      2011/08/20 19:23     Depth 60.4 km      VANUATU
M 7.0      2011/08/20 18:19     Depth 28.5 km      VANUATU
M 5.2      2011/08/20 18:02     Depth 35.3 km      VANUATU
M 5.1      2011/08/20 17:44     Depth 9.5 km      VANUATU
M 5.9      2011/08/20 17:13     Depth 37.3 km      VANUATU
M 5.6      2011/08/20 17:11     Depth 40.9 km      VANUATU

20:51 UTC : GDACS has just published an adapted tsunami map based on the recalculated values of the earthquake.
These are the maximum wave values calculated by GDACS :
00:13     20/08/2011 17:08:15     Montmartre     Vanuatu 1.2
00:13     20/08/2011 17:08:15     Eratap     Vanuatu     1.2
00:15     20/08/2011 17:10:39     Vila     Vanuatu     1.0
00:15     20/08/2011 17:10:39     Port-Vila     Vanuatu 1.0

Map courtesy GDACS

Vanuatu tsunami map August 21 2011 - image courtesy GDACS

20:23 UTC : The Vanuatu Meteorological Service said tsunami waves of 1.05 meter (3.4 feet) arrived on the island of Efate less than an hour after the earthquake. It said there was no damage from the initial waves and has since canceled the advisory.
Tsunami waves of 1 meter can be destructive for close to the sea constructions.  We are awaiting further news from Vanuatu and will let you know immediately when we receive it (as usual).

19:06 UTC : Based on our earlier experiences, we estimate that some damage way have occurred at Efate. Let us hope that no people have been injured or killed.

19:04 UTC : The felt report we have received from Efate does not say anything about damage, but mentioning a VIII MMI (severe shaking) will mean that this earthquake was perceived as violent on the closest island to the epicenter.

18:58 UTC : NOAA published a statement that also the aftersock would NOT generate a widespread tsubnami in the pacific.

18:55 UTC : The website of the Seismological Agency of Vanuatu is not listing this earthquake yet.

18:50 UTC : A massive 7.0 aftershock has hit the same area.  GDACS calculated tsunami heights based on a 7.4 magnitude. It was recalculated later to 7.0, which is a lot less. The aftershock was reported at a depth of 28.5 km. Click here for the epicenter of this massive aftershock.

18:10 UTC : As sais earlier on, NO widespread tsunami was expected on the more remote islands like New Caledonia, Hawaii, etc. etc. Also the pacific coast of the America's and Alaska have NO risk.

18:10 UTC : As predicted before, no news can be found at the moment. The world is publishing a reuters story with some generalities about this earthquake. Nothing you do not know yet.

18:05 UTC : The island closest to the epicenter is Efate with its most important town Port Vila. Port Vila has 35,901 inhabitants).

18:00 UTC : It will probably take a couple of hours before that we can have more information from this remote area in the world.  We do say this on the basis of earlier similar earthquakes.

17:58 UTC : If the tsunami waves will be 2 meters in reality (the predicted height is theoretical), than we can speak from a very severe tsunami on this location.

17:56 UTC : Read also our similar report from the May 10 2011 7.1 earthquake. A 7.5 magnitude earthquake is a lot more stronger than this earthquake. Click here

17:44 UTC : The tsunami waves will probably be higher than the initial 32 cm as written earlier. The tsunmi has ended in all these areas while writing. We know that islanders in Vanuatu tend to autoevacuate very fast to higher ground . 19 minutes will probably be enough to get to higher ground in Efate and other places.00:19     20/08/2011 17:14:29     Montmartre     Vanuatu          1.9
00:20     20/08/2011 17:15:12     MTlT     Vanuatu          1.4
00:20     20/08/2011 17:15:55     Natapao     Vanuatu          1.8
00:20     20/08/2011 17:15:55     Unpongkor     Vanuatu          1.1
00:20     20/08/2011 17:15:55     Forari     Vanuatu          1.1
00:21     20/08/2011 17:16:38     Happy Land     Vanuatu          1.1
00:21     20/08/2011 17:16:38     Umpon Yelonai     Vanuatu          1.1
00:25     20/08/2011 17:20:14     Port-Vila     Vanuatu          1.3
00:25     20/08/2011 17:20:14     Vila     Vanuatu          1.3
00:28     20/08/2011 17:23:07     Loounimhapeun     Vanuatu          1.3
00:29     20/08/2011 17:24:34     Laounalang     Vanuatu          1.2
00:30     20/08/2011 17:25:46     LoounTmeloupang     Vanuatu          1.2

17:38 UTC : WAPMERR, the theoretical damage earthquake engine has calculated that 0 to 1 deaths and 0 to 20 injured may be expected.

17:36 UTC : Our greatest fear goes for the island of Efate with as main city Port Vila. They will have experienced the strongest shaking. However they have a history of very strong earthquakes (a similar earthquake happened a few months ago).

17:35 UTC : The area is currently hit by serious aftershocks

17:34 UTC :The earthquake occurred in the middle of the night.

17:28 UTC :Theoretical calculations are reporting that 33,000 people experienced a very strong shaking, 27,000 people a strong shaking and 62,000 people a moderate shaking

17:21 UTC : GDACS has calculated that the max. tsunami waves (based on theoretical calculations)  have a height of 32 cm (1 foot)

Tsunami animation courtsey GDACS

 

Vanuatu August 20 2011 earthquake - Image courtesy GDACS

17:18 UTC : NOAA tsunami has published the following message for mainland usa :
BASED ON THE EARTHQUAKE MAGNITUDE... LOCATION AND HISTORIC TSUNAMI RECORDS A DAMAGING TSUNAMI IS NOT EXPECTED ALONG THE CALIFORNIA/ OREGON/ WASHINGTON/ BRITISH COLUMBIA AND ALASKA COASTS. AT COASTAL LOCATIONS WHICH HAVE EXPERIENCED STRONG GROUND SHAKING LOCAL TSUNAMIS ARE POSSIBLE DUE
TO UNDERWATER LANDSLIDES.

"I Have Felt It" reports
MMI values (if indicated) after the text (III: Weak shaking, IV Light shaking, V Moderate shaking, VI Strong shaking, VII Very Strong shaking)

Most important Earthquake Data:
Magnitude : 7.5
UTC Time : Saturday, August 20, 2011 at 16:55:02 UTC
Local time at epicenter : Sunday, August 21, 2011 at 03:55:02 AM at epicenter
Depth (Hypocenter) : 40.6
Geo-location(s) :
63 km (39 miles) SSW of PORT-VILA, Efate, Vanuatu
190 km (118 miles) NW of Isangel, Tanna, Vanuatu

Links to important maps
USGS Did You Feel It Map
Google satellite map of the area showing the kind of terrain the earthquake took place
Shakemap
Impact on population map
USGS historic earthquakes map
USGS Seismic hazard map
GDACS earthquake report
GDACS tsunami report

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I did feel it – Ik heb het gevoeld – Το έκανα αισθάνεται – Yo lo siento – 我的确感到了 – 私はそれを感じていました- Ich habe es gefühlt – Bunu hissediyorum yaptı – لم أشعر أنه