Seismicity of the Reykjanes Peninsula 1971–1976

Sveinbjörn Björnsson, Páll Einarsson*, Helga Tulinius, Ásta Rut Hjartardóttir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The Reykjanes Peninsula Oblique Rift, a segment of the mid-Atlantic plate boundary, connects the Reykjanes Ridge to the rift zones of Iceland. The axis of the deformation zone of the plate boundary can be traced as a rather narrow epicentral zone of earthquakes that is highly oblique to the spreading direction of the North America Plate with respect to the Eurasia Plate. The seismicity of the area is episodic. Active periods with a duration of about a decade are separated by more quiet periods of one to two decades. Our observation period spans a good part of an episode that began in 1967 and ended in 1975. Nine earthquake swarms illuminate a 50 km long segment of the plate boundary. The epicentral zone cuts obliquely across the fissure swarms of the volcanic systems of the Peninsula. Geothermal areas are preferentially located at the intersection of the fissure swarms with the seismic zone. Outside the intersections with the seismic zone the fissure swarms show very low seismicity. The tectonic characteristics gradually change along the plate boundary segment, from being similar to those of a spreading segment in the western part to being more like a transform zone in the eastern part. This is seen in the type of earthquake sequences, maximum magnitude, and type of faulting.

Original languageEnglish
Article number106369
JournalJournal of Volcanology and Geothermal Research
Volume391
DOIs
Publication statusPublished - 1 Feb 2020

Bibliographical note

Funding Information:
We wish to thank Lynn. R. Sykes, Peter L. Ward, Fred Klein and Max Wyss of the Lamont Doherty Geological Observatory, Columbia University, USA for invaluable support and cooperation. The National Academy of Sciences in USA supported the project with a substantial grant for equipment. The Reykjanes seismic network was a cooperative project of the National Energy Authority (Orkustofnun) and the Science Institute of the University of Iceland. We thank Gudmundur P?lmason, Geothermal Department of Orkustofnun and prof. Thorbj?rn Sigurgeirsson, Science Institute, for their support of the project. The network enjoyed technical assistance from J?n Sveinsson, Karl Benjam?nsson, Reynir B??varsson, J?sep H?lmj?rn, Gu?bj?rg Arad?ttir, ?orger?ur Sigurgeirsd?ttir and Vilhj?lmur Kjartansson and a large group of students (?smundur Jakobsson, B?ra Bj?rgvinsd?ttir, Birna ?lafsd?ttir, Brynd?s Brandsd?ttir, Egill Hauksson, Gillian R. Foulger, Haukur Arason, Ingibj?rg Haraldsd?ttir, Ing?lfur Hr?lfsson, J?n Steind?r Ingason, Kjartan Magn?sson, Kjartan Ott?sson, L??v?k Georgsson, Sigur?ur Emil P?lsson, Svanbj?rg Haraldsd?ttir, ?orgeir Helgason) got their initial training in field work and data analysis during the operation. Ragnar Stef?nsson and Th?runn Skaftad?ttir kindly provided data on earthquake magnitudes from the permanent network of the Icelandic Meteorological Office.

Publisher Copyright:
© 2018

Other keywords

  • Earthquake sequences
  • Oblique plate boundary
  • Reykjanes peninsula
  • Seismic pattern
  • Seismicity

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