Wednesday, May 13, 2009

Istanbul Earthquake 2009

Istanbul Earthquake 2009
Andre Willers

12 May 2009

Synopsis :

A major earthquake (M>5.6 on Mercalli scale , >= 6.5 on Richter) has a probability of 85% during the remainder of 2009 .

Discussion :

See "Magma Plumes" and "Corkscrew Faults"

The North Anatolian Fault .

(See Nur " Apocalypse" , p240 ISBN 978 0 691 01602 3 )

The 30 year sequence of earthquakes of magnitude>=5.6 propagating along the fault (slippage 1-2 cm/yr) from East to West is :

1939, 1942,1943,1944,1951,1957,1967,1999,2009

The 2009 is unknown , but postulated .

What is the probability of the 2009 quake?
We use a Bayesian type argument .

Differences (yrs):


Error margin +-0.5 . This is Bayesian (ie only the uncertainty at the 2009 level is material . This calculation is done at 13 May 2009 , at which time no earthquake has occurred . The probability is then for the period 13 May 2009 to 31 Dec 2009 .)


1.In the last sixty years , the progression of earthquakes has decreased as they neared the fault-bend near Istanbul . The fault bends towards the south , bypassing Istanbul closely to the South . This increases the friction , and hence the period between quakes .

2. The 2004-2005 massive quakes in Indonesia caused instabilities in the Anatolian Faults . But the recent 2009 quake in Italy means that the destabilization is now also on the Western side of the North Anatolian Fault.

3.Look at the sequence of time differences between the quakes :because it means that it is sequential earthquake-storm , the tensions shift along and we can add the differences . Ie 3+1+2+7+6+10=29 , with an error margin of +-0.5*6 . So , a difference of 32 years(ie the 1999 quakes) is within our error margin .

4.Because these events are happening in 2009 , which is more or equal to 10 years from 1999, we can sum the probabilities :

p(earthquake)=p(3)+p(1)+p(1)+p(7)+p(6)+p(10) (six quakes out of seven)

The destabilization means that all the passed-on slippages come home to roost at once .

As a first approximation , p(earthquake) = 6/7 = 0.85

What does this mean ?

There is a 85% probability of a serious earthquake (Mercalli>=5.6 or Richter>6.5 ) occurring during 13 May 2009 to 31 Dec 2009 with an epicenter close to Istanbul (probably just south of it) , fairly close to the surface . Probably underwater , so tsunamis may be expected .

How big tsunamis?

Large tsunamis can be expected .

Get above the 400 meter mark if you can .

There will be repeated tsunamis . Don't stop and assume you are safe .

The straights subways might survive the quake , only to be crushed by the pressure of the tsunami .

Ditto the bridges .

The waves and seiches from the Sea of Marmara will be ferocious .

Landmass shift :

About 10 – 20 cm . is the estimated distance the Northern part of Anatolia will shift eastward relative to the southern part and the Eastern part of Greece .

This is an awful lot of water between the straights .

Water will rush in from the Black Sea and Sea of Marmara .

In the narrow straights , the wave-heights will be concentrated .

Seiches will wash back-and forth in the Sea of Marmara and Black Sea .

A boat is definitely unsafe .

Isn't geology exciting ?


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