Tuesday, July 1, 2008

Waiting for the big quake

Officials are denying it, so it must be true: the next big Lebanese earthquake is right around the corner. The last few months has witnessed already some 500 (!) minor shakes and tremors, according to Israeli experts. If they can feel it over there, then maybe these quakes are not so minor after all.

For those Lebanese who don't like to panic (um, yeah, right, as if there are any!), please tune to your local expert. Lebanon's National Council for Scientific Research chaired by George Tohme who recently received an honorary doctorate from AUB, has stated there is no reason to worry. Their secretary said that earthquakes are impossible to predict. He then continued that there is no evidence to suggest a large earthquake will strike soon.

Uh-huh. Makes you wonder what he would have said in case there was evidence. Would earthquakes be predictable then, after all? Anyway...

Some people claim that the best method to predict an earthquake is to look at its history because earthquakes tend to happen with a certain frequency. In Lebanon, e.g., major earthquakes happen every 80 years, or so history teaches us. The last big one occurred in 1927, already 81 years ago. Yes, that's right: if history's any guidance, we're one year late for an earthquake!

The pattern for the truly big ones, shows yet another disturbing rhythm, namely every 1500 years, give or take a few. The last superquake to hit Lebanon was back in 550. It wiped out the coastal line of Lebanon and completely destroyed Beirut and Tripoli. Experts claim that 4 such quakes have hit Lebanon during the last 6,000 years before.

Lots of things to worry about. Good thing we have our beloved politicians to keep our mind off of things!


Anonymous said...

This will be Lebanon's reward for worshipping Kuntar the child killer.

Jeha said...

There is good news in all this tectonic movement; these smaller quakes may release the stress on the Tammouneh fault slowly. Otherwise, the stresses would accumulate, leading to a whopper.

However, movement on one fault could shift more stresses onto another fault. In this case, the stresses on the Roum fault would accumulate.

The one thing you can do is live and work in decently built structures. Most of the war and post war stuff is really crappy construction, and would not sustain even a light Richter 6 earthquake. Come to think of it, most of the new ones ain't better; all those stick on panels and glass will easily fall, even in a Ricther 5...

Anonymous said...

I know this post is old, I came across it on a google search. I study earthquakes in the UK.

A few points - its not possible to predict earthquakes. Maybe one day it will be, maybe not. Governments may not be reliable sources, but they really have little idea on this beyond long term risk.

Detecting small earthuakes with seismometers is easy. Its quite possible that an earthquake not felt in Lebanon will still be measured in israel. We can pick up major earthquakes from across the world in the uk, so Israel can measure small ones easily from across the border.

Earthquake 'cycles' are not regular - there may be a long term average but measuring time since the last earthquake doesn't indicate when the next one will be.

To echo Jeha, the big questions are where a big earthquake occurs (roum or yammouneh fault, near big cities?) and how good the local buildings are. Earthquakes are natural, but disasters depend on the human situation.