When is the big sea quake: Why TCO do not provide us data

By Laura SULEIMENOVA

March 11, Kazakh National Data Center [www.kndc.kz] announced a 4.4 earthquake took place in the Caspian Sea.

Two years ago, I dealt with the topic [Tengiz: the surface ascends 5cm a year] and discovered that KNDC is better equipped than Seismology Institute in Almaty.

The quake happened on March 10, at 16.41, Astana time in the territory of the Caspian Sea, 334km south of the Kazakh port of Aktau. It is classified as having magnitude of mb=4.4 and energy class K=10.4.

Over the phone, the head of National Center, Natalya Mikhailova, emphasized it was a regular earthquake in a subsurface range stretching from Turkmenistan to Caucasus:

N.M.: Earthquakes of this kind happen in the area several times a month. Usually their magnitudes are not enough for us to feel on the coast. It should be 5.5-6 to be noticed by humans.

L.S.: But 4.4 is strong enough...

N.M.: You are speaking of magnitude, often confused with amplitude of earthquake. The latter tells about its intensiveness and is measured in points, which give a picture of a quake's nature and impact on earth surface, people, animals, as well as natural and man-made structures in the area affected.

[In this case, it was impossible to determine the scale of amplitude, as it happened in the sea].

L.S.: For Atyrau people the subject is special - the region's oil reserves are extensively being developed at the moment.

N.M.: The reserves, you have in mind, are to the north of the range mentioned.

L.S.: A few years ago, after the earthquake at Tengiz, you spoke of the need to introduce seismic control directly at the field. Has anything changed ever since?

N.M.: As far as I know, TCO has own station, but we do not receive their data. Numerously the issue was raised, also by Seismology Institute, but still no solution.  

Given this, as repeatedly stated by a famous scientist of Atyrau, academician, Mouftakh Diarov, the water zone of the Caspian Sea on the map of seismic activities refers to potential 7 point earthquake areas.

South Caspian Sea bordering with Central Caspian is a zone of active tectonic fractions, where regular earthquakes of various magnitudes take place, of which "echoes" [1-2 point, sometimes 4] reach North Caspian. 

Thus, development of Caspian oil deposits will be executed amid strong natural geodynamic and technogenic factors. There is a significant risk of earthquakes, Diarov predicts.