Saturday, February 16, 2013

In The News: Earthquakes

With the focus on the Middle East and the N Korea/Iran nuclear story, over the past several weeks the earthquake story has been simmering to a higher and higher level. There have been several big quakes and fortunately they were either deep underground or away from heavily populated area, but quakes are again emerging as a story. 

Just today you can see three relatively large quakes and a quick glance at the earthquake map reveals the story:

 The earthquake has been felt in a wide radius which is normal for deep earthquakes. The earthquake waves are propagating from deep in the earth to the upper layers.
Our Philippino readers are reporting relatively high shaking values for this earthquake.
As you can see on the lower map, this is the strongest earthquake in this area for more than a year. The map shows also that the area is seismically very active.
Update 06:10 UTC : Phivolcs published slightly different data than the other agencies : M6.2 at 100 km
Phivolvs did report the following shaking intensities :
Intensity IV – Mati & Taragona, Davao Oriental
Intensity III – Davao City
Intensity II – General Santos City, Butuan City, Malaybalay, Bukidnon
Based on their theoretical models, Phivolcs does not expect any damage out of this earthquake. They expect (as usual) a number of aftershocks.
Update 05:43 UTC : The shaking was theoretically expected to reach a max. V or moderate shaking
A very strong deep earthquake occurred approx. 30 km out of the Mindanao coast. The earthquake was not powerful enough to generate a tsunami.

Most important Earthquake Data:
Magnitude : 6.3
Local Time (conversion only below land) : Unknown
GMT/UTC Time : 2013-02-16 05:16:09
Depth (Hypocenter)  : 294 km
Depth and Magnitude updates in the list below.
Share your earthquake experience (I Have Felt It) with our readers.
Click on the “I Felt It” button behind the corresponding earthquake. Your earthquake experience is not only important for science, but also for people in the area as well as our global readership.

Update 06:20 UTC : The greater epicenter area is seismically very active as one can see on the lower map.  The epicenter is located on top of the subducted plate.
Update 06:01 UTC : The epicenter was at a +200 km out of the coast which makes that the shaking on land was limited to weak or even very weak shaking
A very strong earthquake occurred off the coast of the North Island of New Zealand. The hypocenter was very deep in the hot solid mantle of the earth.

Luckily NO reports of serious damage, but the people in the greater epicenter area are really frightened. Some villages and towns have setup temporary shelters to allow people who are too frightened to sleep there. Others prefer to sleep in their cars.
Update 22:13 UTC : There have not been any reports of major damage as yet and only panic and minor non-structural damage has been seen as yet.
Update 22:00 UTC : This earthquake also caused similar concern from residents of Rome to that of 2009, with calls to emergency services despite no damage.
Update 21:58 UTC : The earthquake was even felt in l’Aquila. Our second map (at the bottom) shows that there were NO other earthquakes in this area since the beginning of 2012.
This earthquake is around the same place as the 1980 Irpinia earthquake causing major damage. This earthquake will normally  only cause minor damage if any presumably.
In 1922 a M5.6 earthquake struck the Sora area and caused some damage too.

 Our biggest concern are the old buildings in Sora. From Emilia Romagna, we know that these are very vulnerable for even moderate shaking. This earthquake can however NOT be compared with that earthquake as the intensity is a lot less.
Update 21:35 UTC : GDACS reports that at least 100,000 people are living within a radius of 10 km from the epicenter
Update 21:33 UTC : INGV Italia is reporting a Magnitude of 4.8 at a depth of 10.7 km

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