Interseismic strain accumulation across the central North Anatolian Fault from iteratively unwrapped InSAR measurements

The North Anatolian Fault (NAF) is a major tectonic feature in the Middle East and is the most active fault in Turkey. The central portion of the NAF is a region of Global Navigation Satellite Systems (GNSS) scarcity. Previous studies of interseismic deformation have focused on the aseismic creep near the town of Ismetpasa using radar data acquired in a single line-of-sight direction, requiring several modeling assumptions. We have measured interseismic deformation across the NAF using both ascending and descending data from the Envisat satellite mission acquired between 2003 and 2010. Rather than rejecting incorrectly unwrapped areas in the interferograms, we develop a new iterative unwrapping procedure for small baseline interferometric synthetic aperture radar (InSAR) processing that expands the spatial coverage. Our method corrects unwrapping errors iteratively and increases the robustness of the unwrapping procedure. We remove long wavelength trends from the InSAR data using GNSS observations and deconvolve the InSAR velocities into fault-parallel motion. Profiles of fault-parallel velocity reveal a systematic eastward decrease in fault slip rate from 30 mm/yr (25–34, 95% confidence interval (CI)) to 21 mm/yr (14–27, 95% CI) over a distance of ∼200 km. Direct offset measurements across the fault reveal fault creep along a ∼130 km section of the central NAF, with an average creep rate of 8 ± 2 mm/yr and a maximum creep rate of 14 ± 2 mm/yr located ∼30 km east of Ismetpasa. As fault creep is releasing only 30–40% of the long-term strain in the shallow crust, the fault is still capable of producing large, damaging earthquakes in this region.

[1]  I. Manighetti,et al.  Generic along‐strike segmentation of Afar normal faults, East Africa: Implications on fault growth and stress heterogeneity on seismogenic fault planes , 2015 .

[2]  Pal Wessel,et al.  The Generic Mapping Tools GMT , 1995 .

[3]  Marie-Pierre Doin,et al.  Improving InSAR geodesy using Global Atmospheric Models , 2014 .

[4]  T. Wright,et al.  Multi-interferogram method for measuring interseismic deformation: Denali Fault, Alaska , 2007 .

[5]  Semih Ergintav,et al.  Creeping along the Ismetpasa section of the North Anatolian fault (Western Turkey): Rate and extent from InSAR , 2005 .

[6]  M. Doin,et al.  Ground motion measurement in the Lake Mead area, Nevada, by differential synthetic aperture radar interferometry time series analysis: Probing the lithosphere rheological structure , 2007 .

[7]  Antonio Pepe,et al.  On the Extension of the Minimum Cost Flow Algorithm for Phase Unwrapping of Multitemporal Differential SAR Interferograms , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[8]  J. Nocquet.  Present-day kinematics of the Mediterranean: A comprehensive overview of GPS results , 2012 .

[9]  Marie-Pierre Doin,et al.  Corrections of stratified tropospheric delays in SAR interferometry: Validation with global atmospheric models , 2009 .

[10]  Tim J. Wright,et al.  Interseismic slip rate of the northwestern Xianshuihe fault from InSAR data , 2009 .

[11]  Semih Ergintav,et al.  Determining and modeling tectonic movements along the central part of the North Anatolian Fault (Turkey) using geodetic measurements , 2011 .

[12]  Demitris Paradissis,et al.  GPS constraints on continental deformation in the Africa‐Arabia‐Eurasia continental collision zone and implications for the dynamics of plate interactions , 2005 .

[13]  C. Werner,et al.  Satellite radar interferometry: Two-dimensional phase unwrapping , 1988 .

[14]  R. Armijo,et al.  Morphology, displacement, and slip rates along the North Anatolian Fault, Turkey , 2002 .

[15]  Rowena B. Lohman,et al.  Some thoughts on the use of InSAR data to constrain models of surface deformation: Noise structure and data downsampling , 2005 .

[16]  A. Hooper.  A Statistical-Cost Approach to Unwrapping the Phase of InSAR Time Series , 2010 .

[17]  J. Beck,et al.  Accounting for prediction uncertainty when inferring subsurface fault slip , 2014 .

[18]  Semih Ergintav,et al.  InSAR velocity field across the North Anatolian Fault (eastern Turkey): Implications for the loading and release of interseismic strain accumulation , 2014 .

[19]  Haluk Ozener,et al.  Seven years of postseismic deformation following the 1999, M = 7.4 and M = 7.2, Izmit-Düzce, Turkey earthquake sequence , 2009 .

[20]  M. Kobrick,et al.  The Shuttle Radar Topography Mapper , 1997 .

[21]  James Jackson,et al.  The 1994 Sefidabeh (eastern Iran) earthquakes revisited: new evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault , 2006 .

[22]  A. Barka,et al.  Slip distribution along the North Anatolian fault associated with the large earthquakes of the period 1939 to 1967 , 1996, Bulletin of the Seismological Society of America.

[23]  S. Jónsson,et al.  Block‐like plate movements in eastern Anatolia observed by InSAR , 2014 .

[24]  Z. Çakır,et al.  Surface creep on the North Anatolian Fault at Ismetpasa, Turkey, 1944–2016 , 2016 .

[25]  Ross D. Hartleb,et al.  Late Holocene slip rate for the North Anatolian fault, Turkey, from cosmogenic 36Cl geochronology: Implications for the constancy of fault loading and strain release rates , 2007 .

[26]  Marie-Pierre Doin,et al.  Systematic InSAR tropospheric phase delay corrections from global meteorological reanalysis data , 2011 .

[27]  Virginie Pinel,et al.  The challenging retrieval of the displacement field from InSAR data for andesitic stratovolcanoes: Case study of Popocatepetl and Colima Volcano, Mexico , 2011 .

[28]  G. J. Mets,et al.  Crustal deformations in the Mediterranean Area computed from SLR and GPS observations , 1996 .

[29]  B. Aktug,et al.  Deformation of Central Anatolia: GPS implications , 2013 .

[30]  Pietro Milillo,et al.  An aseismic slip transient on the North Anatolian Fault , 2016 .

[31]  James H. Dieterich,et al.  Progressive failure on the North Anatolian fault since 1939 by earthquake stress triggering , 1997 .

[32]  T. Wright,et al.  Constraining crustal velocity fields with InSAR for Eastern Turkey: Limits to the block‐like behavior of Eastern Anatolia , 2014 .

[33]  David A. Seal,et al.  The Shuttle Radar Topography Mission , 2007 .

[34]  Bertrand Meyer,et al.  Seismic hazard in the Marmara Sea region following the 17 August 1999 Izmit earthquake , 2000, Nature.

[35]  Tim J. Wright,et al.  Interseismic strain accumulation across the North Anatolian Fault from Envisat InSAR measurements , 2011 .

[36]  Tim J. Wright,et al.  Reassessing the 2006 Guerrero slow‐slip event, Mexico: Implications for large earthquakes in the Guerrero Gap , 2015 .

[37]  C. W. Chen,et al.  Two-dimensional phase unwrapping with use of statistical models for cost functions in nonlinear optimization. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.

[38]  T. Wright,et al.  Geodetic observations of postseismic creep in the decade after the 1999 Izmit earthquake, Turkey: Implications for a shallow slip deficit , 2016 .

[39]  H. Kahle,et al.  GPS and geologic estimates of the tectonic activity in the Marmara Sea region, NW Anatolia , 1997 .

[40]  Mario Costantini,et al.  A novel phase unwrapping method based on network programming , 1998, IEEE Trans. Geosci. Remote. Sens..

[41]  D. McKenzie.  Active Tectonics of the Mediterranean Region , 1972 .

[42]  F. Tupin,et al.  Time series analysis of Mexico City subsidence constrained by radar interferometry , 2009 .

[43]  T. Wright,et al.  Source characteristics of the 6 June 2000 Orta–Çankırı (central Turkey) earthquake: a synthesis of seismological, geological and geodetic (InSAR) observations, and internal deformation of the Anatolian plate , 2007 .

[44]  Tim J. Wright,et al.  InSAR slip rate determination on the Altyn Tagh Fault, northern Tibet, in the presence of topographically correlated atmospheric delays , 2008 .

[45]  Z. Çakır,et al.  Extent and distribution of aseismic slip on the Ismetpaşa segment of the North Anatolian Fault (Turkey) from Persistent Scatterer InSAR , 2014 .

[46]  P. M. Mai,et al.  Evidence for self-similar, triangular slip distributions on earthquakes: Implications for earthquake and fault mechanics. , 2005 .

[47]  R. Finkel,et al.  A late Holocene slip rate for the central North Anatolian fault, at Tahtaköprü, Turkey, from cosmogenic 10Be geochronology: Implications for fault loading and strain release rates , 2009 .

[48]  T. Wright,et al.  Toward mapping surface deformation in three dimensions using InSAR , 2004 .

[49]  A. Hooper,et al.  Recent advances in SAR interferometry time series analysis for measuring crustal deformation , 2012 .

[50]  Z. Çakır,et al.  Monitoring aseismic surface creep along the North Anatolian Fault (Turkey) using ground-based LIDAR , 2011 .

[51]  Robert W. King,et al.  Global Positioning System measurements of present‐day crustal movements in the Arabia‐Africa‐Eurasia plate collision zone , 1997 .

[52]  Edsger W. Dijkstra,et al.  A note on two problems in connexion with graphs , 1959, Numerische Mathematik.

[53]  R. Hanssen,et al.  Radar Interferometry with Public Domain Tools , 2004 .

[54]  Andrew Hooper,et al.  Phase unwrapping in three dimensions with application to InSAR time series. , 2007, Journal of the Optical Society of America. A, Optics, image science, and vision.

[55]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[56]  H. Ozener,et al.  Quantifying aseismic creep on the Ismetpasa segment of the North Anatolian Fault Zone (Turkey) by 6 years of GPS observations , 2013 .

[57]  Andrew Hooper,et al.  A multi‐temporal InSAR method incorporating both persistent scatterer and small baseline approaches , 2008 .

[58]  Robert Tibshirani,et al.  Bootstrap Methods for Standard Errors, Confidence Intervals, and Other Measures of Statistical Accuracy , 1986 .

[59]  T. Wright,et al.  Statistical comparison of InSAR tropospheric correction techniques , 2015 .

[60]  Howard A. Zebker,et al.  Phase unwrapping algorithms for radar interferometry: residue-cut, least-squares, and synthesis algorithms , 1998 .

[61]  T. Wright,et al.  Measurement of interseismic strain accumulation across the North Anatolian Fault by satellite radar interferometry , 2001 .

[62]  Preliminary Results of 1988 and 1990 GPS Measurements in Western Turkey and their Tectonic Implications , 2013 .

[63]  Yehuda Ben-Zion,et al.  Collective behavior of earthquakes and faults: Continuum‐discrete transitions, progressive evolutionary changes, and different dynamic regimes , 2008 .

[64]  H. S. Kutoglu,et al.  Relaxation on the Ismetpasa segment of the North Anatolian Fault after the Golcuk M w = 7.4 and Duzce M w = 7.2 shocks , 2010 .

[65]  Fabio Rocca,et al.  Permanent scatterers in SAR interferometry , 2001, IEEE Trans. Geosci. Remote. Sens..

[66]  New Interpretation as a Paleo,et al.  The North Anatolian Fault Zone: New Interpretation as a Paleo-Benioff Zone , 1975 .

[67]  N. N. Ambraseys,et al.  Some characteristic features of the Anatolian fault zone , 1970 .

[68]  Geoffrey Blewitt,et al.  A geodetic plate motion and Global Strain Rate Model , 2014 .

[69]  Demitris Paradissis,et al.  Global Positioning System constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus , 2000 .

[70]  C. W. Chen,et al.  Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms. , 2000, Journal of the Optical Society of America. A, Optics, image science, and vision.

[71]  D. Sandwell,et al.  Interseismic deformation and creep along the central section of the North Anatolian Fault (Turkey): InSAR observations and implications for rate‐and‐state friction properties , 2013 .

[72]  P. Rosen,et al.  Updated repeat orbit interferometry package released , 2004 .

[73]  J. Ampuero,et al.  Along‐strike change in fault structural maturity due to fault growth controls location of largest earthquake slip and fast rupture , 2016 .

[74]  Tim J. Wright,et al.  Current plate boundary deformation of the Afar rift from a 3‐D velocity field inversion of InSAR and GPS , 2014 .

[75]  Jonathan R Goodman,et al.  Ensemble samplers with affine invariance , 2010 .

[76]  J. Ampuero,et al.  Location of largest earthquake slip and fast rupture controlled by along‐strike change in fault structural maturity due to fault growth , 2016 .

[77]  S. Ergintav,et al.  Interseismic Strain Accumulation in the Marmara Sea Region , 2002 .

[78]  Thomas A. Hennig,et al.  The Shuttle Radar Topography Mission , 2001, Digital Earth Moving.

[79]  Dennis C. Ghiglia,et al.  Two-Dimensional Phase Unwrapping: Theory, Algorithms, and Software , 1998 .

[80]  D. Pantosti,et al.  Preliminary slip rate estimates for the Düzce segment of the North Anatolian Fault Zone from offset geomorphic markers , 2008 .

[81]  J. C. Savage,et al.  Geodetic determination of relative plate motion in central California , 1973 .

[82]  P. Hancock,et al.  Neotectonic deformation patterns in the convex-northwards arc of the North Anatolian fault zone , 1984, Geological Society, London, Special Publications.

[83]  Tim J. Wright,et al.  A spatially variable power law tropospheric correction technique for InSAR data , 2015 .

[84]  Zhenhong Li,et al.  Rapid strain accumulation on the Ashkabad fault (Turkmenistan) from atmosphere‐corrected InSAR , 2013 .

[85]  T. Wright,et al.  Seismicity and subsidence following the 2011 Nabro eruption, Eritrea: Insights into the plumbing system of an off‐rift volcano , 2014 .