Surface creep on the North Anatolian Fault at Ismetpasa, Turkey, 1944-2016


Bilham R., Ozener H., MENCIN D., Dogru A., Ergintav S., Çakır Z. , ...Daha Fazla

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, cilt.121, ss.7409-7431, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 121 Konu: 10
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1002/2016jb013394
  • Dergi Adı: JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
  • Sayfa Sayıları: ss.7409-7431

Özet

We reevaluate the 72 year history of surface slip on the North Anatolian Fault at Ismetpasa since the M-w = 7.4 1944 Bolu/Gerede earthquake. A revised analysis of published observations suggests that days after the earthquake the fault had been offset by 3.7 m and 6 years later by an additional 0.74 m. Creep was first recognized on the fault in 1969 as a 0.13 m offset of a wall constructed in 1957 that now (2016) has been offset by 0.52 m. A carbon rod creep meter operated across the fault in the past 2 years confirms results from an invar wire creep meter operated 1982-1991 that surface slip is episodic. Months of fault inactivity are interrupted by slow slip (<= 10 mu m/d) or multiple creep events with cumulative amplitudes of 2-10 mm, durations of several weeks, and with slip rates briefly exceeding >2.5 mm/h. Creep events accommodate 80% of the surface slip and individually release approximate to 10(-6) shear strain on the flanks of the uppermost 3-7 km of the fault. GPS and interferometric synthetic aperture radar methods yield a current fault slip rate of 7.6 +/- 1 mm/yr suggesting that creep meters incompletely sample the full width of the surface shear zone. The slip rate has slowed from >10 mm/yr in 1969 to 6.1 mm/yr at present, 4.65 mm/yr of which appears to be due to steady interseismic creep driven by plate boundary stressing rates. We calculate that a further 1 m of aseismic surface slip will precede the next major earthquake on the fault assuming an approximate to 260 year main shock recurrence interval on this segment.