Massive earthquake between New Caledonia and Vanuatu

Last update: May 10, 2011 at 11:08 pm by By

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UPDATE 23:00 UTC : A reader staying in Tanna has written this report to earthquake-report.com. We bring it to you as it gives a lot of details on what exactly happened. It read’s like a video clip. Thanks a lot. He indicated the shaking as “very strong”. Tanna was at 134 km from the epicenter and was the closest island. (ER)
This was the strongest earthquake that I have felt since I arrived in Vanuatu (Lenakel, Tanna) 15 months ago.  When It started I didn’t know what was going on, because dogs were barking, but rapidly realized that a rather violent earthquake was starting up.  Over the first 10 seconds it got stronger and stronger, then maintained it’s vigor for about another 15-20 seconds while the walls swayed, everything shook and rattled violently, with a few things falling on the floor. I should explain that I live in a local “traditional” house where the wall consists of 4 layers of concrete blocks into which vertical beams that support the wall, and are connected to the roof joists.  There is a palm thatch roof.  The whole building is very flexible, but sits on a firm concrete base, so the experience is like that of being shaken by a giant hand -an incredible feeling of power.  I went to the US Geological site (bookmarked for such occasions) and noted that the quake was quite shallow – less than 10 Km if I remember correctly, which accounts for the violence.  It is 10:00 am here in Lenakel (I work at the hospital) and I haven’t been down the hill to the town to see what damage (if any) has been caused.  I suspect some stores may have to tidy up the floors beneath their shelves!  When the quake finished there were shouts of joy from those visiting their families – it was the end of visiting hours!

UPDATE 19:01 UTC : Dianne Hambrook in Port Vila, Vanuatu experience report : “We definitely felt that one! The 7.1 in the Loyalty Islands (it didn’t seem that strong but it was quite a long way away). A kind of gentle, rocking and rolling motion that went on for a long time.
We were watching a play and the actors never missed a beat. They carried on performing as if nothing was happening. Impressively professional. Several members of the audience vacated the theatre for the duration though”.

The reports I read said “potentially affecting zero people”. Right!

UPDATE 11:15 UTC : Seismological bureaus have lowered the magnitude from the initial 7.1 to 6.8, seemingly nothing but in earthquake terms a big difference in energy.

UPDATE 11:13 UTC : As expected the first strong aftershock (5.7 magnitude) occurred a little while ago.  There might be some very strong aftershocks to follow, but the aftershocks will be normally harmless and will be gradually winding down from very strong, to strong, to moderate. We will publish the +4.5 aftershocks in our daily earthquake overview, just like we do for the Japan Tohoku earthquake.

UPDATE 10:48 UTC : A reader living in Noumea, New Caledonia reports : I was sitting at a table at an outdoor restaurant and felt weak shaking. MMI II to III

UPDATE 10:27 UTC : Here is the USGS description of the tectonic elements that triggered a similar earthquake in the same area in December 2010. The forces that generated today’s earthquake are the same :

The Vanuatu (New Hebrides trench) earthquake of December 25, 2010, occurred as the result of normal-faulting within the Australia plate, in the region of the boundary between the Australia plate and the Pacific plate. In the epicentral region of the earthquake, the Australia plate moves east-northeast relative to the Pacific plate with a velocity of about 8 cm/yr.
The Australia plate subducts beneath the Pacific plate at the New Hebrides trench and is seismically active northeast of the epicenter of the December 25 earthquake to a depth of 300 km.
The stresses that generated the earthquake result from the bending of the Australia plate as it subducts beneath the Pacific plate.
The New Hebrides arc region of the Australia/New Hebrides plate-boundary experiences numerous strong earthquakes.
In the past quarter century, the thousand kilometer section of the arc centered on the epicenter of the December 25 earthquake has produced 19 earthquakes of magnitude 7 or greater, the largest having magnitude 7.7.
The western margin of the Pacific plate that lies to the east of the New Hebrides trench is commonly viewed as being subdivided into several microplates that move with respect to each other at rates of a few cm/yr.

UPDATE : Earthquake-Report Update Video from Robert Speta based on the content from this article

[youtube iMTa8gDMmt0]

UPDATE 10:18 UTC : Vanuatu will get the highest (relative) waves. First number is the traveling times from the epicenter to the different locations in minutes.
00:17           IlTreup     Vanuatu          0.7 m
00:18           LoonTlapeun     Vanuatu          0.7 m
00:18           LTnakel     Vanuatu          0.7 m
00:18           Loanatom     Vanuatu          0.7 m

UPDATE 10:15 UTC : NO coastal location is expected to receive waves higher than 1 meter.

UPDATE 10:03 UTC : A good image of the expected waves generated by the earthquake. The highest predicted wave measures 80 cm (approx. 3 inch.


UPDATE 10:00 UTC : We expect a lot of aftershocks from this earthquake. The area is almost always very active at lower magnitudes, but moderate to strong magnitude aftershocks maybe expected.

UPDATE 10:00 UTC : The PDF behind this link gives a very good overview of the impact of the similar January 13 earthquake. Click here to view it.

UPDATE 09:53 UTC : Earthquake-Report initial explaining video on this earthquake and green tsunami alart

[youtube RRSiR88Ea6I]

UPDATE 09:50 UTC : Getting felt reports of II and III across New Caledonia and Vanuatu. On the closer islands, IV and a few instances of V are expected but with no damage.

UPDATE 09:48 UTC : USGS is predicting the same percentages as on 13 January 2011, with 0 fatalities expected.

UPDATE 09:45 UTC : Their was only a weak shaking on the nearby islands. Nearby is relative as the distance is at least 100 km away.

UPDATE 09:39 UTC : There was an almost similar earthquake on January 13 2011 without any harm. Click here for our in-depth article on this earthquake

UPDATE 09:37 UTC : A good overview of the historical earthquakes in this area

UPDATE 09:34 UTC : It is interesting to note, that the epicenter is almost identical to that of a M7.0 earthquake that occurred on the 13 January 2011. On that occasion, no damage occurred.

UPDATE 09:31 UTC : Many historic earthquakes have occurred along this trench.

UPDATE 09:28 UTC : Warning : people living on nearby islands should always be aware of a tsunami risk. Local tsunamis can never be excluded.

UPDATE 09:27 UTC : GDACS published a GREEN earthquake and tsunami alert for this earthquake = very limited chance on damage and/or injuries

Tsunami update from PTWC for Hawaii : BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT. A
DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO  TSUNAMI THREAT TO HAWAII.

The New Caledonia / Vanuatu area is known for very strong earthquakes. Today’s earthquake is right on a fault line at a rather safe distance from Wé and Tanna

Most important Earthquake Data:
Magnitude : 7.1 decreased afterwards to 6.8
UTC Time :  Tuesday, May 10, 2011 at 08:55:11 UTC
Local time at epicenter : Tuesday, May 10, 2011 at 07:55:11 PM at epicenter
Depth (Hypocenter) : 26.5 km
Geo-location(s) :
134 km (83 miles) SW of Isangel, Tanna, Vanuatu
149 km (92 miles) NNE of Tadine, Loyalty Islands, New Caledonia

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
USGS historic earthquakes map
USGS Seismic hazard map
USGS Impact on Population map
USGS Shaking map
LIVE SEISMOGRAM (Narrogin, Australia Seismograph station)
GDACS GREEN earthquake report
GDACS GREEN tsunami report
NOAA tsunami report

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The 0.99 US$ QuakeSOS+ version will support the activities of SOS Earthquakes.

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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

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