Seismic crustal structure in Iceland and surrounding area

Flóvenz, Ólafur G.; Gunnarsson, Karl

doi:10.1016/0040-1951(91)90483-9

Cited by 101 publications

(85 citation statements)

References 17 publications

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“…To investigate this model, synthetic tremor is generated with the aid of full wave eld numerical simulations in a realistic topographic and velocity model 24 . Our velocity model is based on a published velocity model in the volcanic zone around Vatnajökull glacier 25 and small-scale refraction seismic studies on volcanoes 26;27 (see gure 5a and Methods). We calculate full wave eld synthetic seismograms at all UR station locations for Ricker .…”

Section: Tremor Models and Tremor Simulationsmentioning

confidence: 99%

“…The remaining models include two Askja velocity models of 47 and 48 and the velocities on the southern end of the 49 velocity model. We also included the velocity model calculated by 25 , who reinterpreted the refraction pro les of 50 with a gradually increasing velocity gradient. The above mentioned velocity models are consistent in depth but P wave velocities near the surface range from 2 to 4 km/s.…”

Section: Velocity Modelmentioning

confidence: 99%

“…We therefore studied the real slownesses of well located earthquakes. We simulated these slownesses in various velocity models and found that the model of 25 Tremor was simulated as a superposition of 'rapidly' repeating 'small' earthquakes. The timing and amplitude of these events were represented using comb-like functions.…”

Section: Velocity Modelmentioning

confidence: 99%

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Tremor-rich shallow dyke formation followed by silent magma flow at Bárðarbunga in Iceland

et al. 2017

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Section: Tremor Models and Tremor Simulationsmentioning

confidence: 99%

Section: Velocity Modelmentioning

confidence: 99%

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Tremor-rich shallow dyke formation followed by silent magma flow at Bárðarbunga in Iceland

et al. 2017

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“…Rai et al [1999] suggest that seismicity is related to lithology that extends into the lower crust. Gahalaut et al [2004], Srinagesh and Sarma [2005], and Sarma and Srinagesh [2007] suggest that sustained seismicity in Koyna-Warna seismic zone is related to the Figure 2. Previously interpreted structures in the Koyna-Warna seismic zone.…”

Section: Journal Of Geophysical Research: Solid Earthmentioning

confidence: 99%

“…There have been 22 earthquakes of M > 5, about 200 earthquakes of M~4, and several thousand smaller earthquakes since 1962. Since the early 1960s, multiple seismicity studies have been carried out in this region to understand seismotectonics of the Koyna-Warna area [Gupta et al, 1969;Guha et al, 1971;Langston, 1981;Rastogi and Talwani, 1980;Langston and Franco-Spera, 1985;Rajendran et al, 1996;Chadha et al, 1997;Gupta et al, 1997;Talwani et al, 1996;Talwani, 1997b;Rastogi et al, 1997;Mandal et al, 1998;Rai et al, 1999;Rastogi and Mandal, 1999;Rajendran and Harish, 2000;Gahalaut et al, 2004;Srinagesh and Sarma, 2005;Sarma and Srinagesh, 2007;Shashidhar et al, 2011]. However, data for most of the previous studies were recorded with relatively few seismographs, and few 3-D velocity models have previously been correlated with the events.…”

Section: Introductionmentioning

confidence: 99%

Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

et al. 2014

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Although seismicity near Koyna Reservoir (India) has persisted for~50 years and includes the largest induced earthquake (M 6.3) reported worldwide, the seismotectonic framework of the area is not well understood. We recorded~1800 earthquakes from 6 January 2010 to 28 May 2010 and located a subset of 343 of the highest-quality earthquakes using the tomoDD code of Zhang and Thurber (2003) to better understand the framework. We also inverted first arrivals for 3-D Vp, Vs, and Vp/Vs and Poisson's ratio tomography models of the upper 12 km of the crust. Epicenters for the recorded earthquakes are located south of the Koyna River, including a high-density cluster that coincides with a shallow depth (<1.5 km) zone of relatively high Vp and low Vs (also high Vp/Vs and Poisson's ratios) near Warna Reservoir. This anomalous zone, which extends near vertically to at least 8 km depth and laterally northward at least 15 km, is likely a water-saturated zone of faults under high pore pressures. Because many of the earthquakes occur on the periphery of the fault zone, rather than near its center, the observed seismicity-velocity correlations are consistent with the concept that many of the earthquakes nucleate in fractures adjacent to the main fault zone due to high pore pressure. We interpret our velocity images as showing a series of northwest trending faults locally near the central part of Warna Reservoir and a major northward trending fault zone north of Warna Reservoir.

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Origin and evolution of the Kolbeinsey Ridge and Iceland Plateau, N-Atlantic

Brandsdóttír

Hooft

Mjelde

et al. 2015

Geochem. Geophys. Geosyst.

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Variations in crustal structure along the 700 km long KRISE7 refraction/reflection and gravity profile, straddling 66.5 N across the Iceland Shelf, Iceland Plateau and western Norway Basin confirm that extinct spreading centers coexisted with the now extinct AEgir Ridge prior to the initiation of the Kolbeinsey Ridge at 26 Ma. The western 300 km of the profile, across the Iceland shelf, formed by rifting at the Kolbeinsey Ridge, whereas the eastern 400 km, across the Iceland Plateau and the western Norway Basin, formed by earlier rifting, possibly containing slivers of older oceanic or continental crust rifted off the central EGreenland margin along with the Jan Mayen Ridge. Crustal thickness increases gradually across the Iceland shelf, from 12 to 13 km near the Kolbeinsey Ridge to 24-28 km near the eastern shelf edge, decreasing abruptly across the shelf edge, to 12-13 km. The Iceland Plateau has crustal thickness ranging from 12 to 15 km decreasing to 5-8 km across the western Norway Basin and 4-5 km at the AEgir Ridge. We suggest that high-velocity lower crustal domes and corresponding gravity highs across the Iceland plateau mark the location of extinct rift axes that coexisted with the AEgir Ridge. Similar lower crustal domes are associated with the currently active rift segments within Iceland and the Kolbeinsey Ridge.

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Seismic crustal structure in Iceland and surrounding area

Cited by 101 publications

References 17 publications

Tremor-rich shallow dyke formation followed by silent magma flow at Bárðarbunga in Iceland

Tremor-rich shallow dyke formation followed by silent magma flow at Bárðarbunga in Iceland

Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

Origin and evolution of the Kolbeinsey Ridge and Iceland Plateau, N-Atlantic

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