Preprints
https://doi.org/10.5194/nhess-2021-15
https://doi.org/10.5194/nhess-2021-15

  04 Feb 2021

04 Feb 2021

Review status: this preprint is currently under review for the journal NHESS.

A Harmonised Instrumental Earthquake Catalogue for Iceland and the Northern Mid-Atlantic Ridge

Kristján Jónasson1, Bjarni Bessason2, Ásdís Helgadóttir1, Páll Einarsson3, Gunnar B. Gudmundsson4, Bryndís Brandsdóttir3, Kristín S. Vogfjörd4, and Kristín Jónsdóttir4 Kristján Jónasson et al.
  • 1Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland, Hjarðarhagi 2, Reykjavík, Iceland
  • 2Faculty of Civil and Environmental Engineering, University of Iceland, Hjarðarhagi 2, Reykjavík, Iceland
  • 3Science Institute, University of Iceland, Sturlugata 7, Reykjavík, Iceland
  • 4Icelandic Meteorological Office, Bústaðavegur 7−9, Reykjavík, Iceland

Abstract. A comprehensive catalogue of historical earthquakes, with accurate epicentres and homogenised magnitudes is a crucial resource for seismic hazard mapping. Here we update and combine catalogues from several sources to compile a catalogue of earthquakes in and near Iceland, in the years 1900–2019. In particular the epicentres are based on local information, whereas the magnitudes are based on teleseismic observations, primarily from international on-line catalogues. The most reliable epicentre information comes from the catalogue of the Icelandic Meteorological Office, but this is complemented with information from several technical reports, scientific publications, newspaper articles, and modified by some expert judgement. The catalogue contains 1272 MW ≥ 4 events and the estimated completeness magnitude is W 5.5 in the first years, going down to MW 4.5 for recent years. The largest magnitude is MW 7.01. Such melting of local and teleseismic data has not been done before for Icelandic earthquakes, and the result is an earthquake map with no obviously mislocated events. The catalogue also lists additional 5654 earthquakes on the Mid-Atlantic Ridge, north of 43°, with both epicentres and magnitudes determined teleseismically. When moment magnitudes are not available, proxy MW values are computed with χ2-regression, normally on MS, but exceptionally on mb. All the presented magnitudes have associated uncertainty estimates. The actual combined seismic moment released in the Icelandic earthquakes is found to be consistent with the moment estimated using a simple plate motion model. The catalogue is named ICEL-NMAR and it is available online at http://dx.doi.org/10.17632/7zh6xg22cv.1.

Kristján Jónasson et al.

Status: open (until 18 Mar 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on nhess-2021-15', Jim Dewey, 27 Feb 2021 reply
  • RC2: 'Comment on nhess-2021-15', Anonymous Referee #2, 01 Mar 2021 reply

Kristján Jónasson et al.

Data sets

ICEL-NMAR Earthquake Catalogue Kristjan Jonasson and Bjarni Bessason https://doi.org/10.17632/7zh6xg22cv.1

Kristján Jónasson et al.

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Short summary
Local information on epicentres and W-magnitudes from international catalogues have been combined to compile a catalogue of earthquakes in and near Iceland in the years 1900–2019. The magnitudes are either moment-tensor modelled or proxy values obtained with regression on MS, or exceptionally on mb. The catalogue also covers the Northern Mid-Atlantic Ridge with less accurate locations but similarly harmonised magnitudes.
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