GPS Constraints on Active Tectonics and Fault Behavior in the E - - PowerPoint PPT Presentation

GPS Constraints on Active Tectonics and Fault Behavior in the E Mediterranean: Focus on the North Anatolian Fault

Robert Reilinger, Robert King, Michael Floyd (DEAPS, MIT) Semih Ergintav (KOERI, Bogazigi U) Philippe Vernant (Geosciences, U of Montpellier II)

OUTLINE

1-GPS and tectonic framework of E Med 2-Faulting and earthquake hazards (focus on Turkey and E Mediterranean)

• Developing simple block models
• Strain accumulation on active faults
• Locked and creep behavior and relationship

to seismicity

1993-2014 GPS sites

915 sGPS sites 372 cGPS sites 723 sigma < 1 mm/yr

GPS Velocities for the AR-AF-EU Plate System

(schematic plate bdries from Bird, 2003) EURASIA AFRICA ARABIA

Morocco 09/2015

Crete_2015

Morocco_2015

Regional Kinematics of AR-AF-EU Plate System

(schematic plate bdries from Bird, 2003) EURASIA AFRICA ARABIA

Something for every Earth Scientist!

Scientific opportunities, but societal hazards

EURASIA AFRICA ARABIA Continental Collision Subduction Cont./Ocean Rift Continental S-S Fault

Block models and Earthquakes

Faults from MTA, Ankara, 2013

(courtesy of H. Karabulut, KOERI)

Seismicity and Crustal structure

A simplified block model

(major faults account for ~90% of deformation)

Anatolia fault strain accum. and internal strain

• f blocks

Anatolia-rigid rotation

Anatolia-fault strain accumulation

Anatolia-rigid rotation Strain accumulation on faults

Locked Faults

Pre-1999 strain accumulation

Postseismic deformation of the 1999 Izmit earthquake between 2003 and 2010

19/21

StaMPS ROI_PAC

Çakir et al., Geology, 2012 20/21

Fault strain accumulation

InSAR Postseismic creep

Fault creep

UNLOCKED LOCKED More distant sites unlocked, closer sites locked; distance reflects depth on fault

Estimating coupling on the Marmara-Izmit segment

50% or ½ locking depth

BUT!

• 1. Mixing pre and post-eq

Fault behavior

• 2. Need segmented models

NAF Marmara Seismic Gap

(Ucarkus, 2010; modified from Armijo et al., 2005)

Marmara Seismic Gap

1999 M7.6 Central Marmara segment Izmit segment (~150 km)

• S. NAF segment

GPS Secular Velocities/Profiles (1994-2013)

(from Ergintav et al., GRL, 2014)

Seismicity constraints on fault behavior

General correlation between creep and seismicity

(Seismicity courtesy of H. Karabulut, KOERI)

Locked Creep Locked

East Anatolian Faults rigid rotation

East Anatolian Fault w/ fault strain accumulation

East Anatolian Fault Seismicity

Caucasus rigid rotation

Caucasus fault strain accumulation

Dead Sea Fault

Rigid Fault strain accumulation

Gulf of Corinth-Kefalonia

Fault strain accum Rigid

Seismicity in Gulf of Corinth

From: Pascal Bernand: http://geo.mff.cuni.cz/seminar/S-140303-Bernard-CRL.pdf

Hellenic Arc plate coupling

Coupling along Hellenic Arc

Hellenic Arc plate coupling

Summary

Anatolia and the NAF

• Very simple elastic block models that include strain accumulation on

active faults account for the large majority of active deformation in Anatolia, and the entire Arabia-Africa-Eurasia zone of plate interactions.

• The NAF is locked and accumulating strain on the Ganos segment, and

from the E end of the 1999 Izmit Earthquake fault to the Karliova Triple Junction.

• The Marmara and Izmit Earthquake segments of the NAF are presently

characterized at least in part by fault creep – for the Izmit segment this behavior started after the 1999 M7.4 Earthquake.

• Continued monitoring and characterizing fault coupling through the

earthquake cycle should provide better estimates of likely eq repeat times along the North Anatolian and other system.

• Perhaps not surprisingly, fault creep along the NAF and at least for some
• ther faults (Corinth, EAF, SAF) correlates to first order with seismicity and

geology – combining seismicity, geodesy, geology, and laboratory studies holds promise for characterizing better the physics of fault creep.

40/21