Seismicity parameters of NW Anatolia: Key Study for Marmara Region

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Özel M.

European Seismological Commission 32nd General Assembly, Montpellier, France, 6 - 10 September 2010, pp.258-259

  • Publication Type: Conference Paper / Summary Text
  • City: Montpellier
  • Country: France
  • Page Numbers: pp.258-259
  • Dokuz Eylül University Affiliated: Yes


Turkey has long been affected by damaging

earthquakes. The recent Tunceli (27.01.2003),

Izmir (10.04.2003 and 17-21.10.2005),

Bingol (01.05.2003, 12-14.03.2005 and

06.06.2005), Denizli (23.07.2003), Elazig

(11.08.2004, 27.12.2007 and 08.03.2010),

Antalya (24.01.2005), Hakkari (25.01.2005)

and Ankara (20-27.12.2007) earthquakes

caused severe damage to life and property

in the country. The Izmit and Duzce earthquakes

(Ms7.4, Ms7.2; August and November

1999) of the NW Anatolia have increased

awareness of the need for seismic disaster

mitigation in Marmara region. Thus, no

part of Turkey is free from earthquake hazard.

Marmara database compiled from

homogeneous earthquake catalogue of Turkey

(Kalafat et al., 2007; KOERI) spans the

time period 1950-2008 in a rectangular area

between 26.0-31.5oE longitudes and 40.0-

41.5oN latitudes. One of the basic seismicity

parameters used to describe an ensemble

of earthquakes is the a- and b-values in the

Gutenberg-Richter frequency magnitude relation.

They characterize the distribution

of earthquakes over the observed range of

magnitudes, and are important parameter

in seismology for its association with several

tectonic features of an area (Scholz, 1968,

Wiemer and Wyss, 1997). It is important to

understand the frequency–magnitude relation

and seismicity parameters (a- and bvalues)

in assessing the earthquake hazard

of a tectonically active region. Starting from

the necessities and views, we performed a

statistical analysis in the Marmara region

following by Gutenberg-Richter magnitudefrequency

distribution. Study area has been

divided into the seven sub-zones according

to the seismotectonic patterns. We detected

a spatial correlation of 2.26-3.79 for aparameter

as indicative for more clustered

events in the region, while the b-value of

0.69-1.18 implies a high tectonic activity in

the region. This result suggests structural

variability and high heterogeneous tectonic

elements in the region. Acknowledgement:

The authors are grateful to the National

Earthquake Observation Center (UDIM) of

the Kandilli Observatory and Earthquake

Research Institute (KOERI), and to Dr. Dogan

Kalafat for accessing earthquake database

via internet ( References:

Kalafat, D., Gunes, Y., Kara, M., Deniz,

P., Kekovali, K., Kuleli, H.S., Gulen, L., Yilmazer,

M. & Ozel, N. 2007. A Revised and

Extended Earthquake Catalogue for Turkey

Since 1900 (M≥4.0), Bogazici University Library

Cataloging, ISBN 978-975-518-281-0,

Istanbul-Turkey, 572p Wiemer, S., and Wyss,

M., 1997. Mapping the frequency-magnitude

distribution in asperities: An improved technique

to calculate recurrence times, Journal

Geophysical Research 102, 15.115-15.128

Scholz, C.H., 1968. The frequency–magnitude

relation of micro fracturing in rock and

its relation to earthquakes, Bulletin Seismological

Society America 58, 399-415