Kandilli Observatory & Earthquake Research Institute Boğaziçi University 81220 Çengelköy/ Istanbul, Turkey

Izmit Earthquake -TURKEY     (first report:18-08-1999)

    Earthquake                                   

• Date: 1999-08-17 at 03:01:37
• Surface Wave Magnitude: 7.8
• Body Wave Magnitude: 6.3
• Duration Magnitude: 6.7

Location

An earthquake of magnitude Md 6.7 (KOERI) occured on North Anatolian Fault Zone with an epicenter near the Gölcük town in the western part of Turkey. The  epicenter was determined to be 40.77N and 29.97E by KOERI with a focal depth of 17km. Macro seismic data indicate an epicentral region directly under Golcuk. The aftershocks whose magnitude equal to or greater than Md 4   recorded  from  KOERI ISK(Istanbul) Station are given.Most of the aftershock activity is confined to the region bounded by 40.5-40.8N and 29.8-30.0E, which covers the area between Izmit and Adapazari to the east of the epicenter.

Seismicity of the Region

Geological Field Observation

Field Rupture

The right lateral displacement offset of NAF between Sapanca Lake and Izmit Gulf was reported as 2.60m.

Extent of the Damage

Majority of damaged or collapsed structures were 4-8 story reinforced concrete buildings

Damage areas in Istanbul and Turkey (under construction)

Peak Accelerations

Bogazici University operates a strong motion array (structural and free field) in and around Istanbul. Information on the array is provided in Strong Motion Statitions in Istanbul and the Marmara Region. The records are being collected and processed.  The preliminary data on peak accelerations at selected stations are given below. The location of the stations can be found in the forementioned link. Note that Yarimca (YPT) station is in the epicentral area.

Photos from Earthquake

General Building Damage in the vicinity of Gölcük (click to enlarge):

  Transportation Damages:

    Highway

Trans European Motorway follows the fault line to the south of Sapanca lake.Overpasses, designed with respect to modified AASHTO specifications, have received varying degrees of damage. A collapsed overpass at Arifiye junction is shown below.

(Hurriyet)

    Railway

Compression failures on the railway track at the south of Sapanca Lake, in the vicinity of fault trace.

Industrial Facilities:

Tupras (Turkish Petroleum Refineries Co.) is the biggest industrial facility in Turkey and the seventh in Europa. The company has the second valuable shares in Istanbul Stock Exchange Market among the others. Nowadays the government is planning to privatize the company which has a total treatment capacity of 27,6 millions of tons of petroleum a year. Tupras has four refineries located in Kırıkkale, Batman, Izmir and Izmit. The refinery in Izmit seen at the pictures below was built in 1961. Due to the earthquake, one of the crude oil tower collapsed . The fire started right after the earthquake can not be controlled by local authorities yet.

Aftershock locations (as of Saturday August 21, 1999)

General Building Damage in the vicinity of Avcilar-Istanbul (click to enlarge):

 

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BBC Photo

Friday, August 20, 1999 Published at 17:42 GMT 18:42 UK World: Europe In pictures: Earthquake three days on Golcuk's mosque remains intact, while surrounding residential buildings have all been rased to the ground.