Abstract
We study the major MW = 7.0, 30 October 2020, Samos earthquake and its aftershocks, by calculating improved locations using differential travel times and waveform cross-correlations. We image the rupture of the mainshock using local strong motion data, and we examine the Coulomb stress evolution prior to the mainshock, as well as the coseismic stress changes. Lastly, we estimate the produced shaking using all the available information from strong motion data and testimonies. Earthquake relocations reveal the activation of the E-W oriented Kaystrios fault, in the North basin of Samos with a possible extension to the West. The kinematic rupture inversion suggests non-uniform bilateral rupture on a ∼60 km × ∼20 km fault area, with the main rupture propagating towards the West and maximum slip up to approximately 2.5 m. Improved locations of the aftershock sequence are anti-correlated with areas of maximum slip on the fault surface. Similarly, the Coulomb stress change calculations show that only off-fault earthquake clusters are located within lobes of increasing positive static stress changes. This observation is consistent with assuming a fault area of either uniform slip, or variable slip according to the obtained slip model. Both scenarios indicate typical stress patterns for a normal fault with E-W orientation, with stress lobes of positive ∆CFF increments expanding in E-W orientation. In the case of the variable slip model, both negative and positive stress changes show slightly larger values compared to the uniform slip model. Finally, Modified Mercalli Intensities based on the fault model obtained in this study indicate maximum intensity (VII +) along the northern coast of Samos Ιsland. Spectral acceleration values at 0.3 s period also demonstrate the damaging situation at Izmir.
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source mechanisms are also plotted in the cross-sections (C-F) oriented perpendicular to the main seismic faults in the study area. The width of each cross-section is set to 5 km. Grey triangles indicate the surface traces of Kaystrios and Pythagorio seismic faults
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References
Akyol N, Zhu L, Mitchell BJ, Sözbilir H, Kekovalı K (2006) Crustal structure and local seismicity in western anatolia. Geophys J Int 166(3):1259–1269. https://doi.org/10.1111/j.1365-246x.2006.03053.x
Altinok Y, Alpar B, Ozer N, Gazioglu C (2005) 1881 and 1949 earthquakes at the chios-cesme strait (aegean sea) and their relation to tsunamis. Nat Hazard 5(5):717–725. https://doi.org/10.5194/nhess-5-717-2005
Aristotle University of Thessaloniki Seismological Network (1981) Permanent regional seismological network operated by the Aristotle University of Thessaloniki. DOI https://doi.org/10.7914/SN/HT, URL http://www.fdsn.org/doi/10.7914/ SN/HT
Armijo R, Meyer B, King GCP, Rigo A, Papanastassiou D (1996) Quaternary evolution of the corinth rift and its implications for the late cenozoic evolution of the aegean. Geophys J Int 126(1):11–53. https://doi.org/10.1111/j.1365-246x.1996.tb05264.x
Askan A, Gulerce Z, Roumelioti Z, Sotiriadis D, Melis N, Altindal A, and; Eyup Sopac BA, Karimzadeh S, Kalogeras I, Theodoulidis N, Konstantinidou K, Ozacar A, Kale O, Margaris B (2021) The Samos island (Aegean Sea) M7.0 earthquake: Analysis and engineering implications of strong motion data. Bulletin of Earthquake Engineering This volume SI
Bassin C, Laske G, Masters TG (2000). The current limits of resolution for surface wave tomography in north america. EOS Trans AGU 81
Benetatos C, Kiratzi A, Ganas A, Ziazia M, Plessa A, Drakatos G (2006) Strike-slip motions in the gulf of Sığacık (western turkey): properties of the 17 October 2005 earthquake seismic sequence. Tectonophysics 426(3–4):263–279. https://doi.org/10.1016/j.tecto.2006.08.003
Beyreuther M, Barsch R, Krischer L, Megies T, Behr Y, Wassermann J (2010) Obspy: a python toolbox for seismology. Seismol Res Lett 81:530–533. https://doi.org/10.1785/gssrl.81.3.530
Bie L, González PJ, Rietbrock A (2017) Slip distribution of the 2015 Lefkada earthquake and its implications for fault segmentation. Geophys J Int 210(1):420–427. https://doi.org/10.1093/gji/ggx171
Bondar I, McLaughlin KL (2009) A new ground truth data set for seismic studies. Seismol Res Lett 80(3):465–472. https://doi.org/10.1785/gssrl.80.3.465
Boore DM, Stewart JP, Skarlatoudis AA, Seyhan E, Margaris B, Theodoulidis N, Scordilis E, Kalogeras I, Klimis N, Melis NS (2021) A ground-motion prediction model for shallow crustal earthquakes in Greece. Bull Seismol Soc Am 111(2):857–874. https://doi.org/10.1785/0120200270
Caputo R, Pavlides S (2013) Greek database of seismogenic sources (gredass). DOI https://doi.org/10.15160/UNIFE/GREDASS/0200, URL http://gredass.unife.it
Worden CB (2016) Shakemap manual. https://doi.org/10.5066/F7D21VPQ
Deng J, Sykes LR (1997) Evolution of the stress field in southern California and triggering of moderate-size earthquakes: a 200-year perspective. J Geophys Res: Solid Earth 102(B5):9859–9886. https://doi.org/10.1029/96jb03897
Disaster And Emergency Management Authority (1990) Turkish national seismic network. DOI https://doi.org/10.7914/SN/TU, URL http://www.fdsn.org/ networks/detail/TU/
Dogan G, Kalligeris N, Yalciner A, Charalampakis M. (2020) Tsunami effects and performance of port structures (chapter 2). In: Seismological and Engineering Effects of the M 7.0 Samos Island (Aegean Sea) Earthquake, Ed: Onder Çetin, K., Mylonakis, G., Sextos, A. and Stewart, J.P., Geotechnical Extreme Events Reconnaissance Association: Report GEER-069
Dogan G, Yalciner A, Yuksel Y, Uluta¸s E, Polat O, Güler I, S¸ahin C, Tarih A, Kanoğlu U (2021). The 30 October 2020 Aegean sea tsunami: post-event field survey along Turkish coast. Pure and applied geophysics pp 1–28
Duputel Z, Tsai VC, Rivera L, Kanamori H (2013) Using centroid time-delays to characterize source durations and identify earthquakes with unique characteristics. Earth Planet Sci Lett 374:92–100. https://doi.org/10.1016/j.epsl.2013.05.024
Dziewonski AM, Chou TA, Woodhouse JH (1981) Determination of earthquake source parameters from waveform data for studies of global and regional seismicity. J Geophys Res: Solid Earth 86(B4):2825–2852. https://doi.org/10.1029/jb086ib04p02825
Ekström G, Nettles M, Dziewoński A (2012) The global CMT project 2004–2010: centroid-moment tensors for 13, 017 earthquakes. Phys Earth Planet Inter 200–201:1–9. https://doi.org/10.1016/j.pepi.2012.04.002
Erickson L (1987) A three-dimensional dislocation program with applications to faulting in the earth: user’s manual for DIS3D. Stanford University, Stanford
Gallovič F, Zahradnik J (2011) Toward understanding slip inversion uncertainty and artifacts: 2 singular value analysis. J Geophys Res. https://doi.org/10.1029/2010jb007814
Gallovič F, Imperatori W, Mai PM (2015) Effects of three-dimensional crustal structure and smoothing constraint on earthquake slip inversions: Case study of the Mw6.3 2009 l'Aquila earthquake. J Geophys Res: Solid Earth 120(1):428–449. https://doi.org/10.1002/2014jb011650
GEER (2020) Samos, Greece earthquake impacts. https://doi.org/10.18118/G6H088, http://geerassociation.org/administrator/components/com_geer_reports/geerfiles/SamosIslandEarthquakeFinalReport.pdf
Harris RA (1998) Introduction to special section: stress triggers, stress shadows, and implications for seismic hazard. J Geophys Res: Solid Earth 103(B10):24347–24358. https://doi.org/10.1029/98jb01576
Helmholtz-Centre Potsdam-GFZ German Research Centre For Geosciences, GEMPA GmbH (2008) The seiscomp seismological software package. DOI https://doi.org/10.5880/GFZ.2.4.2020.003, URL https://www.seiscomp.de/
Hunter JD (2007) Matplotlib: A 2d graphics environment. Computi Sci Eng 9(3):90–95
ITSAK - Institute of Engineering Seismology Earthquake Engineering. 1981 ITSAK Strong Motion Network [Data set]. International Federation of Digital Seismograph Networks https://doi.org/10.7914/SN/HI
Kagan YY (1991) 3-d rotation of double-couple earthquake sources. Geophys J Int 106(3):709–716. https://doi.org/10.1111/j.1365-246x.1991.tb06343.x
Kalligeris N, Skanavis V, Charalampakis M, Melis NS, Voukouvalas E, Annunziato A, Synolakis CE (2021) Field survey of the 30 October 2020 Samos (Aegean Sea) tsunami in the Greek islands. Bull Earthquake Eng. https://doi.org/10.1007/s10518-021-01250-6
Kandilli Observatory And Earthquake Research Institute, Boğaziçi University (1971) Bogazici university kandilli observatory and earthquake research institute. Int Federation Digit Seismog Netw. https://doi.org/10.7914/SN/KO
Kennett BLN, Engdahl ER, Buland R (1995) Constraints on seismic velocities in the earth from traveltimes. Geophys J Int 122(1):108–124. https://doi.org/10.1111/j.1365-246x.1995.tb03540.x
Kim A, Dreger DS (2008) Rupture process of the 2004 Parkfield earthquake from near-fault seismic waveform and geodetic records. J Geophys Res. https://doi.org/10.1029/2007jb005115
King GCP, Stein RS, Lin J (1994) Static stress changes and the triggering of earthquakes. Bulletin of the Seismological Society of America 84(3):935– 953, https://pubs.geoscienceworld.org/bssa/article-pdf/84/3/ 935/2708368/BSSA0840030935.pdf
Kiratzi A (2003) Focal mechanisms of shallow earthquakes in the Aegean Sea and the surrounding lands determined by waveform modelling: a new database. J Geodyn 36(1–2):251–274. https://doi.org/10.1016/s0264-3707(03)00050-4
Kissel C, Laj C (1988) The tertiary geodynamical evolution of the Aegean arc: a paleomagnetic reconstruction. Tectonophysics 146(1–4):183–201. https://doi.org/10.1016/0040-1951(88)90090-x
Konca AO, Hjorleifsdottir V, Song TRA, Avouac JP, Helmberger DV, Ji C, Sieh K, Briggs R, Meltzner A (2007) Rupture kinematics of the 2005 mw 8.6 nias-simeulue earthquake from the joint inversion of seismic and geodetic data. Bull Seismol Soc Am 97(1):S307–S322. https://doi.org/10.1785/0120050632
Konstantinou KI, Mouslopoulou V, Saltogianni V (2020) Seismicity and active faulting around the metropolitan area of Athens, Greece. Bull Seismol Soc Am 110(4):1924–1941. https://doi.org/10.1785/0120200039
Konstantinou K (2018) Estimation of optimum velocity model and precise earthquake locations in ne aegean: implications for seismotectonics and seismic hazard. J Geodyn 121:143–154. https://doi.org/10.1016/j.jog.2018.07.005
Lentas K, Di Giacomo D, Harris J, Storchak DA (2019) The isc bulletin as a comprehensive source of earthquake source mechanisms. Earth Syst Sci Data 11(2):565–578. https://doi.org/10.5194/essd-11-565-2019
Lentas K, Ferreira AMG, Vall´ee M (2013) Assessment of SCARDEC source parameters of global large (mw ≥ 7.5) subduction earthquakes. Geophys J Int 195(3):1989–2004. https://doi.org/10.1093/gji/ggt364
LePichon X, Chamot-Rooke N, Lallemant S, Noomen R, Veis G (1995) Geodetic determination of the kinematics of central Greece with respect to Europe: implications for eastern Mediterranean tectonics. J Geophys Res: Solid Earth 100(B7):12675–12690. https://doi.org/10.1029/95jb00317
Lykousis V, Anagnostou C, Pavlakis P, Rousakis G, Alexandri M (1995) Quaternary sedimentary history and neotectonic evolution of the eastern part of central Aegean sea. Greece Mar Geol 128(1–2):59–71. https://doi.org/10.1016/0025-3227(95)00088-g
Margaris B, Scordilis EM, Stewart JP, Boore DM, Theodoulidis N, Kalogeras I, Melis NS, Skarlatoudis AA, Klimis N, Seyhan E (2021) Hellenic strong motion database with uniformly assigned source and site metadata for the period 1972–2015. Seismol Res Lett 92(3):2065–2080. https://doi.org/10.1785/0220190337
Matrullo E, De Matteis R, Satriano C, Amoroso O, Zollo A (2013) An improved 1-D seismic velocity model for seismological studies in the Cam-paniaLucania region (Southern Italy). Geophys J Int 195(1):460–473. https://doi.org/10.1093/gji/ggt224
McClusky S, Balassanian S, Barka A, Demir C, Ergintav S, Georgiev I, Gurkan O, Hamburger M, Hurst K, Kahle H, Kastens K, Kekelidze G, King R, Kotzev V, Lenk O, Mahmoud S, Mishin A, Nadariya M, Ouzounis A, Paradissis D, Peter Y, Prilepin M, Reilinger R, Sanli I, Seeger H, Tealeb A, Toks¨oz MN, Veis G (2000) Global positioning system constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus. J Geophys Res: Solid Earth 105(B3):5695–5719. https://doi.org/10.1029/1999jb900351
McKenzie D (1972) Active tectonics of the Mediterranean region. Geophys J Int 30(2):109–185. https://doi.org/10.1111/j.1365-246x.1972.tb02351.x
Melis NS, Konstantinou KI (2006) Real-time seismic monitoring in the Greek region: an example from the 17 October 2005 east Aegean Sea earthquake sequence. Seismol Res Lett 77(3):364–370. https://doi.org/10.1785/gssrl.77.3.364
Melis NS, Okal EA, Synolakis CE, Kalogeras IS, Kˆano˘glu U, (2020) The chios, greece earthquake of 23 July 1949: seismological reassessment and tsunami investigations. Pure Appl Geophys 177(3):1295–1313. https://doi.org/10.1007/s00024-019-02410-1
Mountrakis D, Kilias A, Vavliakis E, Psilovikos A, Thomaidou E (2003) Neotectonic map of Samos Island (Agean Sea, Greece): implication of Geographical Information Systems in the Geological mapping. 4th European Congress on Regional Geoscientific Cartography and Information Systems, Bologna, Italy, 11–13
Nalbant SS, Hubert A, King GCP (1998) Stress coupling between earthquakes in northwest turkey and the north aegean sea. J Geophys Res: Solid Earth 103(B10):24469–24486. https://doi.org/10.1029/98jb01491
Nomikou P, Evangelidis D, Papanikolaou D, Lampridou D, Litsas D, Tsaparas Y, Koliopanos I (2021) Morphotectonic analysis along the northern margin of Samos island, related to the seismic activity of october 2020, Aegean Sea. Greece Geosciences 11(2):102. https://doi.org/10.3390/geosciences11020102
National Observatory of Athens, Institute of Geodynamics, Athens (1997) National Observatory of Athens Seismic Network [Dataset]. International Federation of Digital Seismograph Networks. https://doi.org/10.7914/SN/HL
Ocakŏglu N, Demirbağ E, Kuşçu I (2005) Neotectonic structures in Izmir gulf and surrounding regions (western turkey): evidences of strike-slip faulting with compression in the Aegean extensional regime. Mar Geol 219(2–3):155–171. https://doi.org/10.1016/j.margeo.2005.06.004
Papadimitriou EE, Sykes LR (2001) Evolution of the stress field in the northern Aegean Sea (Greece). Geophys J Int 146(3):747–759. https://doi.org/10.1046/j.0956-540x.2001.01486.x
Papazachos BC, Comninakis PE (1971) Geophysical and tectonic features of the Aegean arc. J Geophys Res 76(35):8517–8533. https://doi.org/10.1029/jb076i035p08517
Papazachos CB (1999) Seismological and GPS evidence for the Aegean-Anatolia interaction. Geophys Res Lett 26(17):2653–2656. https://doi.org/10.1029/1999gl900411
Papazachos BC, Papazachou C (2003) The Earthquakes of Greece. Ziti Publications, Thessaloniki, Greece, 286 pp. (in Greek)
Papazachos B, Papadimitriou E, Kiratzi A, Papazachos C, Louvari E (1998) Fault plane solutions in the Aegean Sea and the surrounding area and their tectonic implication. Bollettino Di Geofisica Teorica Ed Applicata 39:199–218
Papazachos B, Scordilis E, Panagiotopoulos D, Papazachos C, Karakaisis G (2004) Global relations between seismic fault parameters and moment magnitude of earthquakes. Bull Geol Soc Greece 36(3):1482–1489
Paradisopoulou PM, Papadimitriou EE, Karakostas VG, Taymaz T, Kilias A, Yolsal S (2010) Seismic hazard evaluation in western turkey as revealed by stress transfer and time-dependent probability calculations. Pure Appl Geophys 167(8–9):1013–1048. https://doi.org/10.1007/s00024-010-0085-1
Parsons T (2002). Global omori law decay of triggered earthquakes: large aftershocks outside the classical aftershock zone. Journal of Geophysical Research: Solid Earth 107(B9):ESE 9–1–ESE 9–20, DOI 10.1029/ 2001jb000646
Pavlides S, Tsapanos T, Zouros N, Sboras S, Koravos G, Chatzipetros A (2009) Using active fault data for assessing seismic hazard: a case study from NE Aegean Sea, Greece. XVIIth Int Conf Soil Mech & Geotechn Eng, 2–3 October 2009, Alexandria, Egypt
QGIS Development Team (2021) QGIS Geographic Information System. QGIS Association, URL https://www.qgis.org
Rhoades DA, Papadimitriou EE, Karakostas VG, Console R, Murru M (2010) Correlation of static stress changes and earthquake occurrence in the north Aegean region. Pure Appl Geophys 167(8–9):1049–1066. https://doi.org/10.1007/s00024-010-0092-2
Schaff D, Waldhauser F (2005) Waveform cross-correlation-based differential travel-time measurements at the northern California seismic network. Bull Seismol Soc Am 95:2446–2461. https://doi.org/10.1785/0120040221
Scholz CH (2002) The Mechanics of Earthquakes and Faulting, 2nd edn. Cambridge University Press, https://doi.org/10.1017/CBO9780511818
Sengör AMC, Satir M, Akkök R (1984) Timing of tectonic events in the menderes massif, western turkey: implications for tectonic evolution and evidence for pan-African basement in Turkey. Tectonics 3(7):693–707. https://doi.org/10.1029/tc003i007p00693
Sladen A, Tavera H, Simons M, Avouac JP, Konca AO, Perfettini H, Audin L, Fielding EJ, Ortega F, Cavagnoud R (2010) Source model of the 2007 Mw8.0 Pisco, Peru earthquake: implications for seismogenic behavior of subduction megathrusts. J Geophys Res. https://doi.org/10.1029/2009jb006429
Sokos E, Zahradník J, Gallovič F, Serpetsidaki A, Plicka V, Kiratzi A (2016) Asperity break after 12 years: the Mw6.4 2015 Lefkada (Greece) earthquake. Geophys Res Lett 43:6137–6145. https://doi.org/10.1002/2016GL069427
Stein RS, Barka AA, Dieterich JH (1997) Progressive failure on the north Anatolian fault since 1939 by earthquake stress triggering. Geophys J Int 128(3):594–604. https://doi.org/10.1111/j.1365-246x.1997.tb05321.x
Stewart JP, Klimis N, Savvaidis A, Theodoulidis N, Zargli E, Athanasopoulos G, Pelekis P, Mylonakis G, Margaris B (2014) Compilation of a local VS profile database and its application for inference of VS30 from geologic and terrain-based proxies. Bull Seismol Soc Am 104(6):2827–2841. https://doi.org/10.1785/0120130331
Stiros S, Laborel J, Laborel-Deguen F, Papageorgiou S, Evin J, Pirazzoli P (2000) Seismic coastal uplift in a region of subsidence: Holocene raised shorelines of samos island, aegean sea, greece. Mar Geol 170(1–2):41–58. https://doi.org/10.1016/s0025-3227(00)00064-5
Styron R, Pagani M (2020) The gem global active faults database. Earthq Spectra 36(1 suppl):160–180. https://doi.org/10.1177/8755293020944182
Tan O (2013) The dense micro-earthquake activity at the boundary between the Anatolian and south Aegean microplates. J Geody 65:199–217. https://doi.org/10.1016/j.jog.2012.05.005
Taymaz T, Jackson J, McKenzie D (1991) Active tectonics of the north and central Aegean Sea. Geophys J Int 106(2):433–490. https://doi.org/10.1111/j.1365-246x.1991.tb03906.x
Technological Educational Institute of Crete (2006) Seismological network of Crete. DOI https://doi.org/10.7914/SN/HC, URL http://www.fdsn.org/doi/10.7914/ SN/HC
Toda S, Stein R, Sevilgen V, Lin J (2011) Coulomb 3.3 graphic-rich deformation and stress-change software for earthquake, tectonic, and volcano research and teaching - user guide. US Geological Survey Open-File Report 1060
University of Athens (2008) Hellenic seismological netowork, University of Athens, seismological laboratory [Data set]. Int Fed Digital Seismograph Netw. https://doi.org/10.7914/SN/HA
University of Patras (2000) University of Patras, seismological laboratory. Int Fed Digital Seismograph Netw. https://doi.org/10.7914/SN/HP
Waldhauser F, Ellsworth WL (2000) A Double-difference earthquake location algorithm: method and application to the Northern Hayward fault, California. Bull Seismolo Soc Am 90(6):1353–1368. https://doi.org/10.1785/0120000006
Waldhauser F, Schaff DP (2008). Large-scale relocation of two decades of northern California seismicity using cross-correlation and double-difference methods. J Geophys Res: Solid Earth, https://doi.org/10.1029/2007jb005479
Wells DL, Coppersmith KJ (1994) New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bull Seismol Soc Am 84(4):974–1002
Wessel P, Smith WHF, Scharroo R, Luis J, Wobbe F (2013) Generic mapping tools: improved version released. EOS Trans Am Geophys Union 94(45):409–410. https://doi.org/10.1002/2013eo450001
Worden CB, Gerstenberger MC, Rhoades DA, Wald DJ (2012) Probabilistic relationships between ground-motion parameters and modified Mercalli intensity in California. Bull Seismol Soc Am 102(1):204–221. https://doi.org/10.1785/0120110156
Zhang L, Mai PM, Thingbaijam KK, Razafindrakoto HN, Genton MG (2014) Analysing earthquake slip models with the spatial prediction comparison test. Geophys J Int 200(1):185–198. https://doi.org/10.1093/gji/ggu383
Acknowledgements
The authors wish to thank two anonymous reviewers for their comments and suggestions which helped to improve the manuscript. The authors gratefully acknowledge the availability of seismograms from IRIS, ORFEUS, and National Data Centres. This research was supported by the ARISTOTLEeENHSP (All Risk Integrated System TOwards Trans-boundary hoListic Early-warning—enhanced European Natural Hazards Scientific Partnership) Project (Contract ECHO/SER/2020/830887+830888). Stress tensors were calculated based on the Dis3D code (Erickson, 1987) and Coulomb 3.4 software (Toda et al., 2011). Waveform data access and processing was carried out using ObsPy (Beyreuther et al., 2010). USGS ShakeMap4 (Worden, 2016) was used to compute shaking. Figures were built using the Generic Mapping Tools (Wessel et al., 2013), QGIS (QGIS Development Team, 2021), and the Matplotlib python library (Hunter, 2007).
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Lentas, K., Gkarlaouni, C.G., Kalligeris, N. et al. The 30 October 2020, MW = 7.0, Samos earthquake: aftershock relocation, slip model, Coulomb stress evolution and estimation of shaking. Bull Earthquake Eng 20, 819–851 (2022). https://doi.org/10.1007/s10518-021-01260-4
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DOI: https://doi.org/10.1007/s10518-021-01260-4