Sunday, July 30, 2017

An Istanbul Earthquake: Since 1939 The Magnitude 7+ Quakes Are Moving Progressively Closer To Istanbul

This is just a heads-up, we are not following in Joe Granville's footsteps* and getting into the earthquake predicting business.

In July 20's "Risk:Today's 6.7-Magnitude Turkish Earthquake Was Not The 'Big One'" we noted:
"The epicenter is just offshore southwestern Turkey while  the 'big one' is expected in Istanbul's backyard...." and mentioned the North Anatolian Fault (NAF):

Here's the problem. The strong earthquakes along the NAF, pictured inside the red crescent in the small map below, have been steadily moving west toward Istanbul, population 14.6 million:
Source: From the USGS via Wikipedia:

The 1939 earthquake was a 7.8 magnitude and killed 32,000.
The 1942 quake, epicenter 200 km further west was a  magnitude 7.0 and killed ~3000.
The 1943 and 1944 earthquakes were both measured at 7.2 and killed 2800 and 3900 respectively.
The 1957 quake, a 7.1, killed 52 people and the 1967 quake also a 7.1 killed 86.

As can be seen in the top panel both of the latter earthquakes resulted in much less lateral slippage of the land compared to the earlier quakes, meaning the stresses were still building.

Finally the 1999 Izmet earthquake—not shown on this 1997 representation—was another 150 km closer to Istanbul. It measured 7.6 and killed over 17,000 people. The lateral slippage was 5.7 meters.

So don't be surprised if one morning in the next 5 to 10 years you wake up and there is some very bad news coming out of Istanbul.

*Our octa- and nona- genarian readers may recall Joe Granville.
From a 2008 post:
NYT, published: January 11, 1981
Joseph Granville doesn't use the word ''forecasting.'' He prefers to say that he applies to the stock market a ''theory'' that he declines to reveal but whose results he communicates to clients in a weekly investment newsletter.
Last week, as his latest bullish issue was still in the mails, Mr. Granville's theory suddenly turned bearish and advised selling. That advice, transmitted to about 3,000 clients in emergency telephone calls, triggered a selloff that drove the Dow Jones industrial average down 23.80 points and resulted in a new one-day volume record on the New York Stock Exchange. The next day, Mr. Granville predicted an earthquake of Richter magnitude 8.3 would hit Los Angeles in May.

From the New York Times:

NOTES ON PEOPLE; As a Seismologist, He's a Good Stock Analyst
April 11, 1981, Saturday
Late City Final Edition, Section 1, Page 16, Column 3, 224 words

When Joseph Granville, the Wall Street analyst, told the 3,000 subscribers to his Granville Market Letter to ''sell everything,'' they had enough faith in him to trigger the Dow Jones industrial Average into tumbling 23.8 points Jan. 8. It was the heaviest trading day in the history of the ...
Always remember that earthquakes can be tricky for equity analysts.