Monitoring of fault healing after the 1999 Kocaeli, Turkey, earthquake

Tadokoro K., Ando M., BARIŞ Ş., Nishigami K., Nakamura M., Ucer S., ...More

JOURNAL OF SEISMOLOGY, vol.6, no.3, pp.411-417, 2002 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 6 Issue: 3
  • Publication Date: 2002
  • Doi Number: 10.1023/a:1020091610510
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.411-417
  • Keywords: fault healing, Kocaeli earthquake, North Anatolian faultzone, S wave splitting, fracture, stress orientation, KEN NANBU EARTHQUAKE, CALIFORNIA, REGION
  • Kocaeli University Affiliated: No


The North Anatolian fault zone that ruptured during the mainshock of the M 7.4 Kocaeli (Izmit) earthquake of 17 August 1999 has been monitored using S wave splitting, in order to test a hypothesis proposed by Tadokoro et al. (1999). This idea is based on the observation of the M 7.2 1995 Hyogo-ken Nanbu (Kobe) earthquake, Japan. After the Hyogo-ken Nanbu earthquake, a temporal change was detected in the direction of faster shear wave polarization in 2-3 years after the main shock (Tadokoro, 1999). Four seismic stations were installed within and near the fault zone at Kizanlik where the fault offset was 1.5 m, about 80 km to the east of the epicenter of the Kocaeli earthquake. The observation period was from August 30 to October 27, 1999. Preliminary result shows that the average directions of faster shear wave polarization at two stations were roughly parallel to the fault strike. We expect that the direction of faster shear wave polarization will change to the same direction as the regional tectonic stress reflecting fault healing process. We have already carried out a repeated aftershock observation at the same site in 2000 for monitoring the fault healing process.