TY - JOUR
T1 - Location accuracy of earthquake hypocentres beneath Eyjafjallajökull, Iceland, prior to the 2010 eruptions
AU - Tarasewicz, Jon
AU - White, Robert S.
AU - Brandsdóttir, Bryndís
AU - Thorbjarnardóttir, Bergthóra
N1 - Funding Information: The temporary stations used in this study are from the LOKI instrument pool, which is jointly owned by the Icelandic Meteorological Office, the Institute of Earth Sciences, Univ. of Iceland and the Iceland GeoSurvey. We thank Martin Hensch, Sveinbjörn Steinþórsson, Þorsteinn Jónsson, Ólafur Guðmunds-son, Benedikt Ófeigsson and numerous other scientists and graduate students who helped with the Eyja-fjallajökull fieldwork. We also thank the landowners at Seljavellir and Núpar for housing the seismic stations sel and nup. The Icelandic Coast Guard helicopter was used to retrieve the gij station following the floods from Gígjökull on April 14th 2010. Julian Drew wrote the CMM software and Hilary Martens developed the Matlab code used for arrival time picking. Finnur Pálsson, Eyjólfur Magnússon and Ásta Rut Hjartardóttir provided digitized data of glacier outlines, eruption sites and tectonic features. Generic Mapping Tools (Wessel and Smith, 1998) were used to produce the figures. We acknowledge thoughtful reviews by Egill Hauksson and Heidi Soosalu. J. T. is funded by a NERC studentship and CASE award supported by ERC Equipoise Ltd. Dept. Earth Sciences, Cambridge, contribution number ESC2249. Funding Information: The temporary stations used in this study are from the LOKI instrument pool, which is jointly owned by the Icelandic Meteorological Office, the Institute of Earth Sciences, Univ. of Iceland and the Iceland GeoSurvey. We thank Martin Hensch, Sveinbjörn Steinþórsson, Þorsteinn Jónsson, Ólafur Guðmundsson, Benedikt Ófeigsson and numerous other scientists and graduate students who helped with the Eyjafjallajökull fieldwork. We also thank the landowners at Seljavellir and Núpar for housing the seismic stations sel and nup. The Icelandic Coast Guard helicopter was used to retrieve the gij station following the floods from Gígjökull on April 14th 2010. Julian Drew wrote the CMM software and Hilary Martens developed the Matlab code used for arrival time picking. Finnur Pálsson, Eyjólfur Magnússon and Ásta Rut Hjartardóttir provided digitized data of glacier outlines, eruption sites and tectonic features. Generic Mapping Tools (Wessel and Smith, 1998) were used to produce the figures. We acknowledge thoughtful reviews by Egill Hauksson and Heidi Soosalu. J. T. is funded by a NERC studentship and CASE award supported by ERC Equipoise Ltd. Dept. Earth Sciences, Cambridge, contribution number ESC2249. Publisher Copyright: © 2011, Iceland Glaciological Society. All rights reserved.
PY - 2011
Y1 - 2011
N2 - The depth of seismicity preceding the 2010 Fimmvörðuháls and Eyjafjallajökull eruptions in South Iceland has implications for the interpretation of the magma plumbing system that was active prior to those eruptions. Significant discrepancies exist in the hypocentral depths reported by different studies of the same earthquakes beneath Eyjafjallajökull in early-mid March 2010. Reported depths range from 3 km to 12 km. We use both real earthquake data and synthetic tests to show that the dominant factor controlling the best-fit hypocentral depths beneath the Eyjafjallajökull glacier is the network configuration. Hypocentral depths of 6–12 km are obtained when only data from permanent seismometer stations operated by the Icelandic Meteorological Office are used, the closest of which is located 13 km from the epicentral zone. Inclusion of data from six temporary seismometer stations deployed around Eyjafjallajökull, all within 4–15 km of the epicentral zone, constrains earthquake depths to be shallower than ∼6 km. A lack of proximal stations on top of the glacier limits resolution of earthquake sources that are shallower than ∼4 km, even when data from the six temporary stations are included. The choice of two plausible distinct velocity models has only a second-order effect on inferred hypocentral depths. We suggest that the true depth of seismicity is ∼2–6 km, which coincides with the depth of inflating magmatic intrusions inferred from surface deformation at that time.
AB - The depth of seismicity preceding the 2010 Fimmvörðuháls and Eyjafjallajökull eruptions in South Iceland has implications for the interpretation of the magma plumbing system that was active prior to those eruptions. Significant discrepancies exist in the hypocentral depths reported by different studies of the same earthquakes beneath Eyjafjallajökull in early-mid March 2010. Reported depths range from 3 km to 12 km. We use both real earthquake data and synthetic tests to show that the dominant factor controlling the best-fit hypocentral depths beneath the Eyjafjallajökull glacier is the network configuration. Hypocentral depths of 6–12 km are obtained when only data from permanent seismometer stations operated by the Icelandic Meteorological Office are used, the closest of which is located 13 km from the epicentral zone. Inclusion of data from six temporary seismometer stations deployed around Eyjafjallajökull, all within 4–15 km of the epicentral zone, constrains earthquake depths to be shallower than ∼6 km. A lack of proximal stations on top of the glacier limits resolution of earthquake sources that are shallower than ∼4 km, even when data from the six temporary stations are included. The choice of two plausible distinct velocity models has only a second-order effect on inferred hypocentral depths. We suggest that the true depth of seismicity is ∼2–6 km, which coincides with the depth of inflating magmatic intrusions inferred from surface deformation at that time.
UR - https://www.scopus.com/pages/publications/84856954959
M3 - Review article
SN - 0449-0576
VL - 2011
SP - 33
EP - 50
JO - Jokull
JF - Jokull
IS - 61
ER -