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Seismological Evidences for Slab Geometry beneath Eastern Mediterranean Sea Ge277-2013 Feb, 20th.

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Presentation on theme: "Seismological Evidences for Slab Geometry beneath Eastern Mediterranean Sea Ge277-2013 Feb, 20th."— Presentation transcript:

1 Seismological Evidences for Slab Geometry beneath Eastern Mediterranean Sea Ge Feb, 20th

2 Tectonic Background Faccenna et. al EPSL Rolling back of Hellenic Trench Indentation Three slab detachments Wortel&Spakman, 2000, Science

3 Papazachos et. al, 2000, Tectonophysics Slab and Benioff-zone Catalog: 1956~1995

4 Papazachos et. al, 2000, Tectonophysics What is the relationship between slab detachment and seismicity depth? NEIC Catalog: 1973 ~ 2013 Slab Geometry and Seismicity Depth > 30km

5 Tomography 1, Travel time tomography 2, Waveform Tomography More waveform information is used but usually rely on good initial model Solving a linearized equation Need a reference model

6 Global Travel Time Tomography Pioneer Wim Spakman 1998, EGU

7 Bijwaard et. al., 1998, JGR P-wave travel time tomography (Global) 5, 000, 000 P, pP, pwP waves picks were used (1964 ~ 1995) Grid size: 0.6*0.6 degree for upper mantle Jolivet, 2010, IJG 1200km

8 Wortel&Spakman, 2000, Science I J Bijwaard&Spakman, 2000, GJI Non-linear inversion Hellenic Slab SouthNorth Hellenic Trench

9 Wortel&Spakman, 2000, Science F E Bijwaard&Spakman, 2000, GJI East West Calabria Slab

10 Wortel&Spakman, 2000, Science G H Bijwaard&Spakman, 2000, GJI West East Carpathians Slab

11 Hinsbergen, 2010, EPSL On going detachment of Hellenic Slab 17.7 million P-wave picks, 3D reference model Resolution for P-wave: 0.8 degree Bijwaard et. al., 1998, JGR Amaru 2007, Geol Ultraiect NS Cyprus

12 Regional Model Faccenna et. al EPSL 1, Asthenosphere 2, Slab remnants 1, P-wave travel time 2, Catalog , Relocated hypocenter 4, 52,000 arrivals 5, Mantle correction Grid size: 0.5*0.5 degree in Mediterranean More regional data than global study

13 Zhu et. al, 2012, NatGeo Waveform Tomography 26, 581 three component waveform data Body wave: 15~50s Surface Wave: 50~150s

14 Zhu et. al, 2012, NatGeo Waveform Tomography

15 Wortel&Spakman, 2000, Science Slab Detachment Faccenna et. al. 2006, EPSL

16 Analogue Lab Experiment Scaling: 1cm -> 70km 1hr -> 1Ma 4.4 mm/hr -> 2.5 cm/yr Slab broke at about 18hr

17 Faccenna et. al EPSL Resolution of tomography Resolution of Tomography

18 Conclusion Seismicity and tomography results indicate the slab break off beneath Cyprus Arc.

19 2Ma ~ now 12~2 Ma 20~12 Ma Transtension Transpression Faccenna et. al EPSL

20 Questions 1, When and where did the slab break off? (evidence) 2, Is there any relationship between slab break off and the acceleration of retreat of the Hellenic trench? 3, What is the relationship between the indentations, the westward motion on NAF and slab break off?


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