The Seismicity in the Eastern Marmara Sea after the 17 August 1999 Izmit Earthquake

Karabulut, Hayrullah; Bouin, Marie‐Paule; Bouchon, Micheĺ; Dietrich, Michel; Cornou, Cécile; Aktar, Mustafa

doi:10.1785/0120000820

Cited by 74 publications

(105 citation statements)

References 8 publications

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“…[52,62,63]). The focal mechanism studies in Armutlu Peninsula showed that most earthquakes are characterized by normal faulting [14,34,36,44]. Also, variations are also due to different crustal structures, thickness, rock types, physical properties and ultimately its degree of heterogeneity.…”

Section: Resultsmentioning

confidence: 99%

“…A complete understanding of the historical and instrumental seismicity, tectonics, geology, paleoseismology, and other neotectonic properties of the considered region are necessary for an ideal delineation of seismic source zones. Microseismicity and seismotectonics of the eastern part of the Marmara Sea, have been discussed by several researchers following the 1999 Izmitearthquake (e.g., [14,16,17,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]). Using all available research results, earthquake epicenters from 2000 to 2014, with a magnitude greater than Mw ≥ .…”

Section: Data Processingmentioning

confidence: 99%

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Spatial Analysis of b-value Variability in Armutlu Peninsula (NW Turkey)

Yeken

2016

Open Geosciences

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Spatial variations of b values were studied by means of 2376 earthquakes with a magnitude completeness of 2.7 in the Armutlu Peninsula (NW Turkey) during a 15-year period following the destructive earthquake on August 17, 1999 in Kocaeli. The b value of L6 for the entire Armutlu Peninsula represents a large value for a global value, but this analysis suggested that the distribution of b value around the Armutlu Peninsula varied extensively from 1.2 to 2.6. Several pockets of high bvalue re ected changes in the physical properties of the Armutlu Peninsula. The southern part of the peninsula represents a lower b value against the northern part of the peninsula. A high bvalue was observed around Termal and Armutlu towns where plenty of geothermal springs occur. Seismic tomography studies revealed a low velocity zone beneath the Termal area where the high b value was imaged in this study. A seismic swarm which is considered to be related with geothermal activity also occurred in 2014 at the same place. This observation suggests that it is possible to propose that the high b value in the northern part of the peninsula could be related to hydrothermal/geothermal activity which contributes to lowering the e ective stress.

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Section: Resultsmentioning

confidence: 99%

Section: Data Processingmentioning

confidence: 99%

Spatial Analysis of b-value Variability in Armutlu Peninsula (NW Turkey)

Yeken

2016

Open Geosciences

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“…The seismic moment tensor solutions have been determined by seismic moment tensor waveform inversion ISOLA (Sokos & Zahradnik, 2006) method using the near-field and regional waveforms. Source parameters (strike, dip and rake), seismic moment and moment magnitude values of these earthquakes are obtained from deviatoric moment tensor analyses using a suitable crustal model (Karabulut et al, 2002), seismograms and catalogue data. High-quality broadband earthquake data have been selected and the data have been filtered in the range of 0.02-0.09 Hz.…”

Section: Moment Tensor Solution and Stress Tensor Analysismentioning

confidence: 99%

8 January 2013 Mw = 5.7 North Aegean Sea earthquake and its seismotectonic significance

et al. 2014

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The deformation of the North Aegean Sea is mainly controlled by the westernmost segments of North Anatolian Fault System. On 8 January 2013, a moderate earthquake (Mw = 5.7) occurred in the North Aegean Sea. A series of aftershocks were occurred within four months following the mainshock, which have magnitudes varying from Ml = 0.9 to 5.0. We have obtained a total of 23 earthquake moment tensor solutions that belong to the 2013 earthquake sequence. The source of this earthquake sequence is a N75°E trending pure dextral strike-slip fault. The temporal and spatial distribution of the earthquakes indicate that the rupture unilaterally propagates from SW to NE. The stress tensor analysis shows that the direction of the regional compressive stress is WNW-ESE. The 1968 Aghios earthquake (Ms = 7.3) and the 2013 North Aegean Sea earthquake sequences indicate that the regional stress has been transferred from SW to NE in this region. The 1672 Bozcaada earthquake (M = 7.0) had been occurred to the north-east of the 2013 earthquake sequence. The elapsed time (342 year) and the regional stress transfer point out that the 1672 earthquake segment is probably a seismic gap and it is a potential earthquake hazard for this region.

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“…Some of these modelled scenarios correspond to epicentres of events that had struck Istanbul in the past (e.g., event 1 mimics the 1999 M 7.4 Izmit Earthquake, and event 7 simulates the 1912 M 7.4 Earthquake in Ganos). Next, assuming a common depth of 10 km for all the scenarios and using the P-and S-wave velocity model proposed by Karabulut et al (2002) (Table 1), theoretical P-wave arrival times were computed for the IERRS stations by the program TauP (Crotwell et al, 1999). Finally, these P-times data sets are used as input for the REL strategy.…”

Section: Application To Synthetic Datamentioning

confidence: 99%

“…With this regard, Figure 1 illustrates what happens when a standard localization procedure such as Hypoellipse (Lahr, 1999), a well-established location algorithm, is used with the IERRS arrival-time data-set in order to locate the epicentre of an earthquake occurring outside of the network. Considering an event that occurred in the Marmara Sea on September 29th, 2004 (see section 4 for further details about this event) and using the 1D velocity model proposed by Karabulut et al (2002) ( Table 1), Figure 1a presents the inversion results provided by Hypoellipse for the cases when only the P-wave arrival times are used and when both the P and S wave times are considered. Usually, in order to provide information about the error associated with the localization estimate, the standard error ellipse produced by Hypoellipse is shown.…”

Section: Introductionmentioning

confidence: 99%

A generalized zero-lag cross-correlation approach for Rapid Earthquake Localization (REL): the example of the Istanbul Megacity Rapid Response System

et al. 2011

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SUMMARYA seismic antenna approach based on the generalized zero-lag cross-correlation method for rapid earthquake localization is proposed. This method is intended to be applied primarily for early warning, whenever the epicentre-to-target distances guarantee enough lead-time, rapid response purposes, and for those circumstances when a seismogenic area is not directly accessible with seismic stations or/and a network of instruments is concentrated within the area to be warned. The procedure we propose aims to provide useful information for magnitude determination and shake-maps generation. Indeed, it relies only on the first P-wave triggered arrivals from seismic stations, and is designed to work in real time for the localization of events occurring outside of the network, that is, under conditions that might be detrimental to standard localization approaches. The procedure can by summarized by a few preliminary pre-seismic and real-time co-seismic steps. In the pre-seismic time-frame, for the cases where a large and dense network exists, waiting for all stations to trigger could dramatically reduce the available lead-time for the warning. Therefore, in such cases the network could profitably be divided into sub-arrays, while also taking advantage of available earthquake recordings or simulated data-sets. During the co-seismic time-frame, the main operations are: 1) individual on-site triggering by the P-wave of the seismic stations (e.g. by a STA/LTA algorithm); 2) real-time communication of key parameters (e.g., P-wave arrival time, and signal quality) to a main centre by SMS/WLAN; 3) setup of a pseudo data set, composed by a Gaussian function centred at the P-time, and with a bell width that can be set up proportional to the trigger signal-to-noise ratio (SNR); 4) calculation of a coherency map for the sub-array with triggered stations (preliminary sub-array location); and 5) stacking of coherency maps from the different sub-arrays (final location). By the stack of coherency maps estimated by the different sub-arrays in the last step of the procedure, the epicentral area's location may be better constrained. This innovative approach for rapid localization was applied to both synthetic data, and real observations of two small earthquakes that occurred in the Marmara Sea, Turkey, which were recorded by the Istanbul Earthquake Rapid Response System.

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The Seismicity in the Eastern Marmara Sea after the 17 August 1999 Izmit Earthquake

Cited by 74 publications

References 8 publications

Spatial Analysis of b-value Variability in Armutlu Peninsula (NW Turkey)

Spatial Analysis of b-value Variability in Armutlu Peninsula (NW Turkey)

8 January 2013 Mw = 5.7 North Aegean Sea earthquake and its seismotectonic significance

A generalized zero-lag cross-correlation approach for Rapid Earthquake Localization (REL): the example of the Istanbul Megacity Rapid Response System

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