Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 Acta Geophysica

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: wschodnie Morze Egejskie

Sortuj według:

Ogranicz wyniki do:

Short term clustering modeling of seismicity in Eastern Aegean Sea (Greece): a retrospective forecast test of the 2017 Mw =6.4 Lesvos, 2017 Mw =6.6 Kos and 2020 Mw =7.0 Samos earthquake sequences

Kourouklas Christos, Mangira Ourania, Console Rodolfo, Papadimitriou Eleftheria, Karakostas Vassilios, Murru Maura

Acta Geophysica

2021

Vol. 69, no. 3

1085--1099

Short-term earthquake clustering properties in the Eastern Aegean Sea (Greece) area investigated through the application of an epidemic type stochastic model (Epidemic Type Earthquake Sequence; ETES). The computations are performed in an earthquake catalog covering the period 2008 to 2020 and including 2332 events with a completeness threshold of Mc=3.1 and separated into two subcatalogs. The frst subcatalog is employed for the learning period, which is between 2008/01/01 and 2016/12/31 (N=1197 earthquakes), and used for the model’s parameters estimation. The second subcatalog from 2017/01/01 to 2020/11/10 (1135 earthquakes), in which the sequences of 2017 Mw=6.4 Lesvos, 2017 Mw=6.6 Kos and 2020 Mw=7.0 Samos main shocks are included, and used for a retrospective forecast testing based on the constructed model. The estimated model parameters imply a swarm like behavior, indicating the ability of earthquakes of small to moderate magnitude above Mc to produce their own ofsprings, along with the stronger earthquakes. The retrospective evaluation of the model is examined in the three aftershock sequences, where lack of foreshocks resulted in low predictability of the mainshocks, with estimated daily probabilities around 10–5. Immediately after the mainshocks occurrence the model adjusts with notable resemblance between the expected and observed aftershock rates, particularly for earthquakes with M≥3.5.

Seismotectonic implications of the 2020 Samos, Greece, Mw 7.0 mainshock based on high resolution aftershock relocation and source slip model

Karakostas V., Tan O., Kostoglou A., Papadimitriou E., Bonatis P.

Acta Geophysica

2021

Vol. 69, no. 3

979--996

The 30 October 2020, Mw 7.0 Samos mainshock took place in the ofshore north of Samos Island in eastern Aegean area, previously struck in 1904 with a comparable magnitude earthquake ofshore the southern coastline. The investigation of the aftershock seismicity evolution and the properties of the activated fault network was accomplished with aftershock relocation performed with the double-diference and cross-correlation techniques. The highly accurate relocated seismicity illustrates a well-defned E–W activated structure located deeper than 5 km with an average depth of~12 km. Moment tensor solutions indicate mostly normal faulting with an average T-axis~ 185ο . Strong-motion waveform modeling revealed a N-dipping fault plane with a coseismic slip patch of 36 km × 22 km and a maximum slip equal to 1 m at 12 km depth. The slip is mainly concentrated in a single asperity implying a rupture mode of asperities breaking in isolated earthquakes rather than to cooperate to produce a larger rupture. Coulomb stress calculations unveil increased positive static stress changes values at the locations of the majority of the aftershocks and activation of minor fault segments by stress transfer.

A detailed analysis of microseismicity in Samos and Kusadasi (Eastern Aegean Sea) areas

Tan O., Papadimitriou E. E., Pabuccu Z., Karakostas V., Yoruk A., Leptokaropoulos K.

Acta Geophysica

2014

Vol. 62, no. 6

1283--1309

A detailed investigation of microseismicity and fault plane solutions are used to determine the current tectonic activity of the prominent zone of seismicity near Samos Island and Kusadasi Bay. The activation of fault populations in this complex strike-slip and normal faulting system was investigated by using several thousand accurate earthquake locations obtained by applying a double-difference location method and waveform cross-correlation, appropriate for areas with relatively small seismogenic structures. The fault plane solutions, determined by both moment tensor waveform inversions and P-wave first motion polarities, reveal a clear NS trending extension direction, for strike slip, oblique normal and normal faults. The geometry of each segment is quite simple and indicates planar dislocations gently dipping with an average dip of 40-45°, maintaining a constant dip through the entire seismogenic layer, down to 15 km depth.