A snapshot (2003–2005) of the 3D postseismic deformation for the 1999, Mw=7.4 İzmit earthquake in the Marmara Region, Turkey, by first results of joint gravity and GPS monitoring

Ergintav, Semih; Doǧan, Uǧur; Gerstenecker, C.; Çakmak, R.; Belgen, Alpay; Demirel, Hüseyin; Aydin, Cüneyt; Reilinger, Robert

doi:10.1016/j.jog.2006.12.005

Cited by 37 publications

(31 citation statements)

References 47 publications

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“…From long experience, the instruments used are known as high accuracy and robust instruments with low and stable drift rates (Atzbacher and Gerstenecker, 1993;Ergintav et al, 2007;Jentzsch et al, 2004;Kanngieser et al, 1983). Regarding the desired accuracy of ±10 nm/s 2 , the calibration, their stability, and systematics of the instruments are important.…”

Section: Calibrationmentioning

confidence: 99%

“…The stability of the linear calibration factors of the instruments used has been proven over decades in campaigns carried out by Atzbacher and Gerstenecker (1993); Ergintav et al (2007); Jentzsch et al (2004); Kanngieser et al (1983). Furthermore, the calibration values obtained on the Hanover-Harz line at different campaigns were compared with each other.…”

Section: Calibrationmentioning

confidence: 99%

“…Ergintav et al (2007) investigated temporal gravity changes due to postseismic deformations in the Marmara region, Turkey. They obtained accuracies of up to ±100 nm/s 2 by deploying two relative instruments (point distances of several 10 km and a gravity range of some 100 µm/s 2 ).…”

Section: Introductionmentioning

confidence: 99%

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Detection of small hydrological variations in gravity by repeated observations with relative gravimeters

Naujoks

Weise

Kröner

et al. 2007

J Geod

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Abstract. Recently, a new application of timedependent gravity observations is emerging: the study of natural hydrological mass changes and their underlying processes. Complementary to GRACE data and continuous recordings with superconducting gravimeters, repeated observations with relative instruments on a local network may contribute to gain additional information on spatial changes in hydrology. The questions that need to be addressed are whether the results of these repeated measurements will be of sufficiently high resolution and accuracy, as well as how unique the information obtained will be. To examine this, a local gravity network with maximum point distances of 65 m was established in a hilly area around the Geodynamic Observatory Moxa, Germany. Using three to five LaCoste & Romberg relative gravimeters repeated measurements were carried out in a seasonal rhythm as well as at particular events like snowmelt or dryness in 17 campaigns between November 2004 and April 2007. The standard deviations obtained by least squares adjustment range from ±9 nm/s 2 to ±14 nm/s 2 for a gravity difference of one campaign, thus for gravity changes between two campaigns from ±13 nm/s 2 to ±20 nm/s 2 . Between the points of the network, spatial gravity changes of up to 171 nm/s 2 (139 nm/s 2 between two successive campaigns) could be proven significantly. They correlate with changes in the local hydrological situation. Particularly, a steep slope next to the observatory is identified as a gravimetrically significant hydrological compartment. The results obtained contribute to an improved reduction of the local hydrological signal in continuous gravity recordings and provide constraints to hydrological models.

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Section: Calibrationmentioning

confidence: 99%

Section: Calibrationmentioning

confidence: 99%

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Detection of small hydrological variations in gravity by repeated observations with relative gravimeters

Naujoks

Weise

Kröner

et al. 2007

J Geod

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“…Several geophysical and geodetic observations have been concentrated in this area for the studies of seismicity, tectonic i.e. Reilinger et al 2000Reilinger et al , 2006Bürgmann et al 2002;Ergintav et al 2007Ergintav et al , 2009Hearn et al 2009). Among these observations, gravity measurements can assist to verify vertical crustal deformation models and to contribute to the improvement of correction models, which are necessary to separate temporal vertical crustal movements induced by ocean, atmospheric and ground water loading effects from the long-term processes (Lambert 1994;Ergintav et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Since our objective is different from the previous study, there are not any identical stations with our study. Additionally, after the 1999 earthquakes, the repeated relative gravity observations were carried out to determine gravity changes in time and space related to vertical crustal movements and subsurface mass changes (Ergintav et al 2007). Ergintav et al (2007) reported a snapshot of the 3D postseismic deformations of the Izmit earthquake from the long term joint relative gravity and GPS monitoring in the Marmara region.…”

Section: Introductionmentioning

confidence: 99%

Establishment of a gravity calibration baseline with the constrain of absolute gravity measurements after 17 August 1999 Izmit earthquake in Marmara region, Turkey

et al. 2013

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We described the first results of an on-going study of absolute gravity changes after the 17 August 1999 Izmit earthquake in Marmara region. Repeated absolute gravity measurements were carried out six stations with an A10 absolute gravimeter from 2009 to 2011 in the region. A gravimetric calibration baseline (of the range of about 415 milliGal (mGal), 1 mGal = 10 −5 ms −2 ) was established in the region for the purposes of the calibration of the relative gravimeters. The absolute gravity measurements, repeated twice a year (October, June), can resolve gravity changes with a precision better than 5 microGal (μGal)/yr interval.The absolute gravity stations indicate a statistically significant gravity decrease at one of the absolute gravity stations in the calibration baseline, but the other stations do not. Generally, the absolute gravity difference agrees well with the general trend of the relative gravity changes. In addition, the precise vertical gravity gradients with relative gravity measurements have been determined at the absolute gravity stations for the reduction of measured gravity to the benchmark. The gradients scatter around the nominal constant (3.086 μGal/cm) between 2.82-3.73 μGal/cm as a result of the local density anomalies. The difference from the nominal gradient causes the error around 7-14 μGal by applying the normal vertical gradient instead of the directly measured one.

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Seismicity distribution and locking depth along the Main Marmara Fault, Turkey

Schmittbuhl

Karabulut

Lengliné

et al. 2016

Geochem Geophys Geosyst

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The seismicity along the Main Marmara Fault (MMF) below the Marmara Sea is analyzed during the 2007-2012 period to provide insights on the recent evolution of this important regional seismic gap. High precision locations show that seismicity is strongly varying along strike and depth providing fine details of the fault behavior that are inaccessible from geodetic observations. The activity strongly clusters at the regions of transition between basins. The Central basin shows significant seismicity located below the shallow locking depth inferred from GPS measurements. Its b-value is low and the average seismic slip is high. All observations are consistent with a deep creep of this segment. On the contrary, the Kumburgaz basin at the center of the fault shows sparse seismicity with the hallmarks of a locked segment. In the eastern Marmara Sea, the seismicity distribution along the Princes Island segment in the Cinarcik basin, is consistent with the geodetic locking depth of 10 km and a low contribution to the regional seismic energy release. The assessment of the locked segment areas provide an estimate of the magnitude of the main forthcoming event to be about 7.3 assuming that the rupture will not enter significantly within creeping domains.

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A snapshot (2003–2005) of the 3D postseismic deformation for the 1999, Mw=7.4 İzmit earthquake in the Marmara Region, Turkey, by first results of joint gravity and GPS monitoring

Cited by 37 publications

References 47 publications

Detection of small hydrological variations in gravity by repeated observations with relative gravimeters

Detection of small hydrological variations in gravity by repeated observations with relative gravimeters

Establishment of a gravity calibration baseline with the constrain of absolute gravity measurements after 17 August 1999 Izmit earthquake in Marmara region, Turkey

Seismicity distribution and locking depth along the Main Marmara Fault, Turkey

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