The slip deficit on the North Anatolian Fault (Turkey) in the Marmara Sea: insights from paleoseismicity, seismicity and geodetic data

TL;DR

This study combines seismic, paleoseismic, and geodetic data to assess the slip deficit on the North Anatolian Fault in the Marmara Sea, predicting a future Mw 7.4-7.5 earthquake due to accumulated strain.

Contribution

It provides a comprehensive analysis of the slip deficit and models the potential size of future earthquakes on the fault segment using an integrated dataset.

Findings

Identifies a significant slip deficit of Mw ~7.4-7.5 for future earthquakes.

Models the seismic gap and estimates the moment rate deficit.

Suggests a future earthquake with ~3.25 m slip could occur.

Abstract

The North Anatolian Fault experienced large earthquakes with 250-400 years recurrence time. In the Marmara Sea region, the 1999 (Mw = 7.4) and the 1912 (Mw = 7.4) earthquake ruptures bound the Central Marmara Sea fault segment. Using historical-instrumental seismicity catalogue and paleoseismic results (~2000-year database), the mapped fault segments, fault kinematic and GPS data, we compute the paleoseismic-seismic moment rate and geodetic moment rate. A clear discrepancy appears between the moment rates and implies a significant delay in the seismic slip along the fault in the Marmara Sea. The rich database allows us to identify and model the size of the seismic gap and related fault segment and estimate the moment rate deficit. Our modeling suggest that the locked Central Marmara Sea fault segment even including a creeping section bears a moment rate deficit $M_d = 6.4 \times 10^{17}$ N.m./yr that corresponds to Mw ~ 7.4 for a future earthquake with an average ~3.25 m coseismic slip. Taking into account the uncertainty in the strain accumulation along the 130-km-long Central fault segment, our estimate of the seismic slip deficit being ~10 mm/yr implies that the size of the future earthquake ranges between Mw = 7.4 and 7.5.