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This Issue's Bannergram |
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KIV BHZ D=10° Mw=7.4
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The seismogram above (and on page 1) is a broadband, vertical component recording of the Magnitude (Mw) 7.4 earthquake that devastated parts of western Turkey on August 17, 1999. The recording shows the ground motion at the IRIS GSN station KIV near Kislovodsk, Russia, about 1,000km northeast of the earthquake epicenter. Loss of life and damage to structures were massive. More than 15 thousand people were killed in the earthquake, over 24 thousand injured. The estimated total economic loss due to the earthquake exceeds $16 billion. Collapsed and damaged buildings alone amount to over $5 billion. Most damaged structures were 4-8 story reinforced concrete buildings such as the one shown in the photo above. The technical causes that contributed to the observed damage to buildings include poor concrete quality, poor detailing of reinforcements, and structural alterations. The earthquake occurred along the northern strand of the North Anatolian Fault Zone (NAFZ), one of the best studied strike-slip faults in the world. According to reports from Turkish and USGS field crews, the main shock produced more than 100 km of surface rupture. Right-lateral offsets as large as 5 meters were observed along the entire length of the rupture. In the photo (left) railroad tracks running between the cities of Izmit and Arifiyi are offset by 2.7 meters. The NAFZ is known as the most prominent active fault in Turkey. Since 1939, the NAFZ has produced seven earthquakes with magnitudes (Ms) larger than 7.0. These earthquakes have ruptured the fault progressively from east to west, creating distinct regions of enhanced stress levels. In 1997, a study of stress changes along the fault estimated a 12% probability that within the next 30 years a major earthquake may occur in the region of the NAFZ now effected by the August 17 earthquake. For more information and data from the earthquake, please visit our special event page on the Turkish earthquake at www.iris.edu |
Staff News |
IRIS Newsletter |
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The IRIS Data Management Center was happy to welcome Mary Edmunds to the staff in July, 1999, as a Data Control Technician. Mary is from the Seattle area, and was previously working for the University of Washington. She has a background in the Earth sciences and has been a very welcome addition to the group that archives and processes the large number of requests that come through the Center. We want to congratulate Chau Tran and Christina Jenkins in the IRIS business department. Both delivered beautiful babies this summer. Chau's family has another baby girl, Hien; and Christina delivered her first baby, Benjamin. All are doing well. |
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2 times per year by the IRIS Consortium. IRIS Newsletter The Incorporated Research Institutions for Seismology (IRIS) is a university consortium of over 90 research institutions dedicated to monitoring the Earth and exploring its interior through the collection and distribution of geophysical data. IRIS programs contribute to scholarly research, education, earthquake hazard mitigation, and the verification of the Comprehensive Test Ban Treaty. IRIS operates through a Cooperative Agreement with the National Science Foundation under the Division of Earth Science's Instrumentation and Facilities Program. Funding is provided by the National Science Foundation, the Department of Energy, the National Imagery and Mapping Agency, other federal agencies, universities, and private foundations. All IRIS programs are carried out in close coordination with the US Geological Survey and many international partners. The IRIS Newsletter welcomes contributed articles. Please contact one of the editors or send your submission to the address above.
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