Relocation of recent seismicity and seismotectonic properties in the Gulf of Corinth (Greece)

Mesimeri, Maria; Karakostas, V.; Papadimitriou, Eleftheria; Tsaklidis, George; Jacobs, Katrina

doi:10.1093/gji/ggx450

Cited by 29 publications

(33 citation statements)

References 66 publications

(104 reference statements)

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“…The relocated earthquake catalog is available as supporting information. We calculate relative location uncertainties using 200 bootstrap resamplings (Efron & Gong, ) and the approach described by Mesimeri et al (). We resample the residuals derived from the final double‐difference inversion, add them to the differential times of each event with unit weights, and repeat the relocation for each resample.…”

Section: Resultsmentioning

confidence: 99%

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Michailos

Smith

Chamberlain

et al. 2019

Geochem Geophys Geosyst

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The Alpine Fault is an oblique strike‐slip fault that is known to fail in large magnitude (M7–8) earthquakes, yet it is currently seismically quiescent. We examine the low‐magnitude earthquake activity occurring along the central portion of the Alpine Fault using seismic data from five temporary seismic networks deployed for various lengths of time between late 2008 and early 2017. Starting from continuous seismic data, we detect earthquake arrivals and construct the longest and most extensive microearthquake catalog for the central Alpine Fault region to date, containing 9,111 earthquakes. This enables us to study the distribution and characteristics of the seismicity in unprecedented detail. Earthquake locations are constrained by high‐quality automatic and manual picks, and we perform relocations using waveform cross‐correlation to better constrain hypocenters. We have derived a new local magnitude scale calibrated by Mw values. Magnitudes range between ML−1.2 and 4.6, and our catalog is complete above ML 1.1. Earthquakes mainly occur southeast of the Alpine Fault (in the hanging wall) and exhibit low magnitudes. We observe a lack of seismicity beneath Aoraki/Mount Cook, which we associate with high uplift rates and high heat flow. Seismogenic cutoff depths vary along the strike of the Alpine Fault from 8 km, beneath the highest topography, to 20 km in the adjacent areas.

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Section: Resultsmentioning

confidence: 99%

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Michailos

Smith

Chamberlain

et al. 2019

Geochem Geophys Geosyst

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“…The maximum hypocenter separation allowed of 10 km discards 24% of the events, reducing the number of relocated events from 2,655 to 2013 (open purple circles in Figure ). Because the uncertainties in the final locations estimated by hypoDD using the LSQR method are grossly underestimated (Waldhauser & Ellsworth, ), we assess them independently using a bootstrap resampling method (Mesimeri et al, ) in which relocation is repeated for 100 samples. The median 95% confidence error ellipse semimajor axis lengths for all the events are ~592, 358, and 426 m in the model‐aligned x , y , and z directions, respectively.…”

Section: Relocation Resultsmentioning

confidence: 99%

Crustal Fault Connectivity of the M_w 7.8 2016 Kaikōura Earthquake Constrained by Aftershock Relocations

Lanza

Chamberlain

Jacobs

et al. 2019

Geophysical Research Letters

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The 14 November 2016 Mw7.8 Kaikōura earthquake in the northern South Island, New Zealand, involved highly complex, multifault rupture. We combine data from a temporary network and the permanent national seismograph network to repick and relocate ~2,700 aftershocks of M≥3 that occurred between 14 November 2016 and 13 May 2017. Automatic phase‐picking is carried out using REST, a newly developed hybrid method whose pick quality is assessed by comparing automatic picks for a subset of 138 events with analysts' picks. Aftershock hypocenters computed from high‐quality REST picks and a 3‐D velocity model cluster almost exclusively in the shallow crust of the upper plate and reveal linkages at depth between surface‐rupturing fault segments. Only eight aftershocks are relocated on a deeper structure positioned between patches of geodetically detected afterslip. This indicates that afterslip has not triggered significant earthquake activity on the subduction interface during the period of aftershock activity analyzed.

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“…Earthquakes occurred since 1900 with M ≥ 6.0 are shown by stars (Papazachos & Papazachou 2003). Red circles show earthquakes occurred during 2008-2014 (Mesimeri et al 2018). The stations of the Hellenic Unified Seismological Network are displayed by triangles.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, the entire waveform database of the western Corinth Gulf (Mesimeri et al 2018) was searched for multiplets of repeating events by applying waveform cross-correlation in a window that includes almost the entire seismogram. A detailed spatio-temporal analysis is performed along with the estimation of the amount of slip released in each repeating sequence and the investigation of recurrence intervals' regularity.…”

Section: Introductionmentioning

confidence: 99%

Repeating earthquakes in western Corinth Gulf (Greece): implications for aseismic slip near locked faults

Mesimeri

Karakostas

2018

Geophysical Journal International

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An extensive search for repeating earthquakes was performed in the western Corinth Gulf by applying waveform cross-correlation on 22 000 earthquakes that occurred in 2008-2014. Event pairs with high correlation coefficient (CC ≥ 0.95) recorded by two or more stations are classified as multiplets of repeating events. The highly similar event pairs have typically interevent distances less than a quarter wavelength (∼150 m for a dominant frequency of 10 Hz) and are used to estimate the accuracy of the relocated catalogue. A detailed analysis of the spatio-temporal properties of the repeating sequences revealed two types of repeating events, namely, burst-like and continuous-type repeaters. Burst-like repeaters are widespread in the entire study area, mostly associated with seismic excitations located at depths between 5 and 9 km, triggered either by fluid intrusion or stress transfer. Their duration is short with high values of coefficient of variation in recurrence intervals (COV > 1) and high slip rates. The continuous-type repeaters, which last 1-7 yr, with COV ∼ 1 and slip rates almost 0.26 cm yr −1 , form a very narrow shallow north-dipping seismic zone at 10 km depth along the Psathopyrgos and Aigion faults. That kind of activity provides strong evidence for aseismic slip in the western Corinth Gulf and defines the boundary between brittle and ductile layers in the area.

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Relocation of recent seismicity and seismotectonic properties in the Gulf of Corinth (Greece)

Cited by 29 publications

References 66 publications

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Crustal Fault Connectivity of the M_w 7.8 2016 Kaikōura Earthquake Constrained by Aftershock Relocations

Repeating earthquakes in western Corinth Gulf (Greece): implications for aseismic slip near locked faults

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Relocation of recent seismicity and seismotectonic properties in the Gulf of Corinth (Greece)

Cited by 29 publications

References 66 publications

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Variations in Seismogenic Thickness Along the Central Alpine Fault, New Zealand, Revealed by a Decade's Relocated Microseismicity

Crustal Fault Connectivity of the Mw 7.8 2016 Kaikōura Earthquake Constrained by Aftershock Relocations

Repeating earthquakes in western Corinth Gulf (Greece): implications for aseismic slip near locked faults

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Crustal Fault Connectivity of the M_w 7.8 2016 Kaikōura Earthquake Constrained by Aftershock Relocations