Philippines quake kills four in Cebu

not sure what news you are reading but as far as i know lots more damage was caused in bohol http://www.abs-cbnnews.com/nation/regions/10/16/13/siquijor-under-state-calamity

They are getting better at it. Like medicine.

Bohol's Seven Quakes Today
1. Magnitude 4.9 Quake at 4:40 am, 8km SW of Bagacay, Talibon, Bohol
2. Magnitude 4.7 Quake at 5:11 am, 3km SW of Doljo, Panglao, Bohol
3. Magnitude 4.9 Quake at 5:29 am, 7km NW of Danao, Bohol
4. Magnitude 4.9 Quake at 5:43 am, 3km SW of Hinlayagan Ilaud, Trinidad, Bohol
5. Magnitude 4.9 Quake at 9:45 am, 3km ENE of Catigbian, Bohol
6. Magnitude 4.7 Quake at 2:23 pm, 7km ESE of Catigbian, Bohol
7. Magnitude 5.2 Quake at 4:05 pm, 7km W of Loon Bohol

wow..........

I notice the exception here is Palawan....

Bohol quake is a warning of things to come, experts warn

"Experts warn that many parts of the Philippines—including the nation's densely-populated capital—are long overdue for major earthquakes, and we can't entirely be sure where the next big one will strike.
But one thing is for certain: it's only a matter of time.
Mario Aurelio, Laboratory Head of the Structural Geology and Tectonics of the UP National Institute of Geological Sciences (NIGS) laments the lack of comprehensive knowledge about the country's numerous geologic faults.
The 7.2 magnitude earthquake that shook Central Visayas on October 15 was a relatively rare event, Aurelio notes, but other parts of the country are also due for similar quakes.
Earthquake-prone areas
“Bohol and Cebu earthquakes have been relatively rare, considering that the entire Philippine archipelago is earthquake-prone except for Palawan,” said Mario Aurelio, Laboratory Head of the Structural Geology and Tectonics of the UP National Institute of Geological Sciences (NIGS).
“('Yung Bohol at Cebu) hindi naman kasing active ng mga considered na very active faults tulad ng sa Siargao and Zambales,” said Ric Mangao, research specialist from the Philippine Institute of Volcanology and Seismology (Phivolcs)."

http://ph.news.yahoo.com/bohol-quake-warning-things-come-experts-warn-120148976.html

I also noticed this line.....limestone blocks......well I'll be fooked, thats exactly what I said...hence no rebar.

"Old churches don't have rebars, the metal skeletons that serve as the foundation of a structure and hold it together. Instead, they were built by piling blocks of limestone, one on top of another."

Palawan is sufficiently far enough away from the fault then? Understood on the limestone blocks but surprised to see Cebu Doctors damaged, it's only about 5 years old.

Palawan is on a different plate completely to the rest of the Philippines. That's why it appears on the hazard maps as low or very low risk, seismically. So yes, the faults that are seismically active in the rest of the Philippines dont head out to Palawan.

Geologically there is a subduction zone between Palawan and the rest of the Philippines.

There are quite a few references to it out there. The Philippines are a group of volcanic islands and Palawan isnt......and I suspect it is the reason why offshore Palawan is particularly hydrocarbon rich.....


http://philippinecommentary.blogspot.com/2010/01/safest-place-to-be-palawan-but.html

Wikipedia seems to summarise it okay....

http://en.wikipedia.org/wiki/Palawan

They still have earthquakes but so do we in the UK, but the cause and magnitude are of different origin.

Seems they (PHIVOLCS) are suggesting a new fault here:-

http://anc.yahoo.com/video/phivolcs...ion_ref_map={"745280345489525":"facebook_cb"}

Ok on the Wiki link too

Nice video. I posted something on this a week or two back. Basically the Philippine archipelago sits as a small and seperate plate, between two much bigger plates, that are virtually squeezing in from either side. The Philippines is the meat in the plate tectonics sandwich, hence all the faulting and volcanics - they are inevitable. The Pacific Ocean is closing and something has to give and its the Philippines that is being crushed like a walnut in nutcracker, but very slowly.

The analogy with the vice and walnut is a simplistic one as there is some relief from in that the plates either side of the Philippines are sliding underneath it, but the Philippines still feels some of the lateral pushing and shoving.

Not only that some of the force is also coming up from the south and the two plates either side arent directly opposite one another so there is a "skewed" effect.

This thread has a good illustration of the plates and subduction zones but only in the north...Luzon.

http://www.british-filipino.com/sho...quakes&p=38337&highlight=Subduction#post38337

Quoting my own writing :

"On a day to day basis, these stresses build up with little to no movement until eventually something somewhere has to give within the fault system i.e. an earthquake event occurs.
The fact that stress is continually being applied means that an earthquake somewhere in Luzon (and other areas in the Philippines) is always likely to happen at any time. "

Very interesting John. Just to close for tonight here are the latest USGS reports:-

Four new quakes shook Bohol and Cebu this morning (USGS):
* 1st Quake (4:11 am): Magnitude 4.7, 3km SW of Doljo, Panglao, Bohol;
* 2nd Quake (4:29 am): Magnitude 4.9, 7km NW of Danao, Bohol;
* 3rd Quake (4:43 am): Magnitude 4.9, 3km SW of Hinlayagan Ilaud, Trinidad, Bohol; and
* 4th Quake (9:45 am): Magnitude 4.9, 3km ENE of Catigbian, Bohol.

Hi, I am a newbie in this forum. I have a family in bulacao pardo. My family still traumatized at the moment!! I live in dorset.

Hello; welcome here. I hope your family are OK.

The VERY bad thing about Manila, from the earthquake point of view, is that it is built on clay and mud, not rock. When I lived there, 18 years ago, the "folklore" was that the only building that would withstand an earthquake was the Shangri-La Hotel.

Still rocking and rollin.. Last one about 20 mins ago..
2013-10-21 07:03:24 9.63 N 123.97 E 5.2 NEGROS- CEBU REG, PHILIPPINES

Welcome! So sorry to hear about your family! I have lots of relatives in Cebu that are still traumatised, Thanks God! they are fine!

My nanay was having breakfast when the big one started shaking her house,
she finished it before leaving, then calmly went back in to drink her coffee lol, she's seen it all before. Then all the family
Started to climb to higher grounds fear of tsunami

Earth Science 4th Ed., 1958 defines Karst topography as surface limestone dissolved by water charged with carbon dioxide in air along rock fissures that can be enlarged into sink holes sometimes filled with water to produce lakes. If sink holes are numerous, drainage of the entire region may be underground with no surface streams.

1] This describes Bohol.

2] Notice the link between carbon dioxide, water and limestone.

And for the Daily Mail affecionados:

New supercontinent 'Amasia' will form over the Arctic with North and South America fusing together (in 200million years)

http://www.dailymail.co.uk/sciencet...ctic-North-South-America-fusing-together.html

Strong quake moved part of Bohol to Cebu - Phivolcs

"The magnitude 7.2 earthquake that hit parts of Central Visayas last Oct. 15 moved part of Bohol closer to Cebu, the Philippine Institute of Volcanology and Seismology (Phivolcs) said yesterday.

Phivolcs director Renato Solidum said the powerful quake - which left more than 200 people dead - moved Bohol, including Tagbilaran City, by 55 centimeters ( 1ft 9 1/2" ) west towards Cebu."

http://www.abs-cbnnews.com/nation/regions/12/06/13/strong-quake-moved-part-bohol-cebu-phivolcs


"Meanwhile, Solidum said they would release next year a new tool to help ordinary households evaluate if their houses are safe during earthquakes.

Phivolcs has partnered with the Japan International Cooperation Agency in developing a questionnaire, composed of 12 questions related to the structural integrity of their houses.

The questionnaire dubbed "How safe is my house?" will be available to the public through the agency's website" www.phivolcs.dost.gov.ph