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

Roger Bilham*, H. Ozener, D. Mencin, A. Dogru, S. Ergintav, Z. Cakir, A. Aytun, B. Aktug, O. Yilmaz, W. Johnson, G. Mattioli

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

We reevaluate the 72 year history of surface slip on the North Anatolian Fault at Ismetpasa since the Mw = 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 µm/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 ≈ 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 ≈ 260 year main shock recurrence interval on this segment.

Original languageEnglish
Pages (from-to)7409-7431
Number of pages23
JournalJournal of Geophysical Research: Solid Earth
Volume121
Issue number10
DOIs
Publication statusPublished - 1 Oct 2016

Bibliographical note

Publisher Copyright:
©2016. The Authors.

Funding

The project was funded by NSF grants EAR 1349851/1622720 and by Scientific Research Projects of Bogazici University under grant 10240. We thank Clarence Allen, James Jackson, and Wayne Thatcher for providing us with their original photographs of the wall at Ismetpasa and Frank Wyatt for providing us with a measure of the pen length in the Rustrak recorders with which we corrected nonlinearity in the 1987 chart records. The manuscript has been substantially improved following thoughtful reviews by Jim Lienkaemper, Sylvain Barbot, the Associate Editor, and an anonymous reviewer. We acknowledge the importance of independent evaluation of the Ismetpasa data, and the supporting information provide copies of the photographs used in our analysis and digital listings of the 1982–1991 and 2014–2016 creep meter data.

FundersFunder number
Clarence Allen
James Jackson
Scientific Research Projects of Bogazici University10240
National Science FoundationEAR 1349851/1622720

    Keywords

    • 1944 Bolu earthquake
    • afterslip
    • creep meter
    • fault creep
    • North Anatolian Fault

    Fingerprint

    Dive into the research topics of 'Surface creep on the North Anatolian Fault at Ismetpasa, Turkey, 1944–2016'. Together they form a unique fingerprint.

    Cite this