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Lower-crustal earthquakes caused by magma movement beneath Askja volcano on the north Iceland rift

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Abstract

The lower crust of magmatically active rifts is usually too hot and ductile to allow seismicity. The Icelandic mid-Atlantic rift is characterized by high heat flow, abundant magmatism generating up to 25–30 km thick crust, and seismicity within the upper 8 km of the crust. In a 20-seismometer survey in July-August 2006 within the northern rift zone around the Askja volcano we recorded ~1700 upper-crustal earthquakes cutting off at 7–8 km depth, marking the brittle-ductile boundary. Unexpectedly, we discovered 100 small-magnitude (ML <1.5) earthquakes, occurring in swarms mostly at 14–26 km depth within the otherwise aseismic lower crust, and beneath the completely aseismic middle crust. A repeat survey during July-August 2007 yielded more than twice as many lower-crustal events. Geodetic and gravimetric data indicate melt drainage from crustal magma chambers beneath Askja. We interpret the microearthquakes to be caused by melt moving through the crust from the magma source feeding Askja. They represent bursts of magma motion opening dykes over distances of a few meters, facilitated by the extensional setting of the active rift zone.

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References

  • Almendros J, Ibáñez J, Carmona E, Zandomeneghi D (2007) Array analyses of volcanic earthquakes and tremor recorded at Las Cañadas caldera (Tenerife Island, Spain) during the 2004 seismic activation of Teide volcano. J Volcanol Geotherm Res 160:285–299

    Article  Google Scholar 

  • Angenheister G, Gebrande H, Miller H, Weigel W, Jacoby WR, Pálmason G, Björnsson S, Einarsson P, Pavlenkova NI, Zverev SM, Litvinenko IV, Loncarevic B, Solomon SC (1980) Reykjanes Ridge Seismic Experiment (RRISP 77). J Geophys 47:228–238

    Google Scholar 

  • Boettcher MS, Hirth G, Evans B (2007) Olivine friction at the base of oceanic seismogenic zones. J Geophys Res 112:B01205. doi:10.1029/2006JB004301

    Article  Google Scholar 

  • Buck WR, Einarsson P, Brandsdóttir B (2006) Tectonic stress and magma chamber size as controls of dike propagation: Constraints from the 1975–1984 Krafla rifting episode. J Geophys Res 111:B12404. doi:10.1029/2005JB003879

    Article  Google Scholar 

  • Chouet B (1996) Long-period volcano seismicity: its source and use in eruption forecasting. Nature 380:309–316

    Article  Google Scholar 

  • Darbyshire FA, White RS, Priestley KF (2000) Structure of the crust and uppermost mantle of Iceland from a combined seismic and gravity study. Earth Planet Sci Lett 181:409–428

    Article  Google Scholar 

  • de Zeeuw-van Dalfsen E, Rymer H, Sigmundsson F, Sturkell E (2005) Net gravity decrease at Askja volcano, Iceland: constraints on processes responsible for continuous caldera deflation, 1988–2003. J Volcanol Geotherm Res 139:227–239

    Article  Google Scholar 

  • DeMets C, Gordon RC, Argus DF, Stein S (1994) Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions. Geophys Res Lett 21:2191–2194

    Article  Google Scholar 

  • Drew J, Leslie D, Armstrong P, Michaud G (2005) Automated microseismic event detection and location by continuous spatial mapping. SPE Annual Technical Conference and Exhibition, Dallas, Texas, 9–12 October 2005, SPE 95513

  • Drew J (2008) Microseismic event detection and location by continuous map migration. USPTO Patent 20060062084, European Patent EP1789820

  • Einarsson P (1991) Earthquakes and present-day tectonism in Iceland. Tectonophysics 189:261–279

    Article  Google Scholar 

  • Einarsson P, Brandsdóttir B (1980) Seismological evidence for lateral magma intrusion during the July 1978 deflation of the Krafla volcano in NE-Iceland. J Geophys 47:160–165

    Google Scholar 

  • Einarsson P, Sæmundsson K (1987) Earthquake epicenters 1982–1985 and volcanic systems in Iceland (map). In: Sigfússon ÞI (ed) Í hlutarins eðli, Festscrift for Þorbjörn Sigurgeirsson, Menningarsjóður, Reykjavík

  • Foulger GR, Du Z, Julian BR (2003) Icelandic-type crust. Geophys J Int 155:567–590

    Article  Google Scholar 

  • Gebrande H, Miller H, Einarsson P (1980) Seismic structure of Iceland along RRISP-profile I. J Geophys 47:239–249

    Google Scholar 

  • Hasegawa A, Zhao D, Hori S, Yamamoto A, Horiuchi S (1991) Deep structure of the northeastern Japan arc and its relationship to seismic and volcanic activity. Nature 352:683–689

    Article  Google Scholar 

  • Hill DP, Prejean S (2005) Magmatic unrest beneath Mammoth Mountain, California. J Volcanol Geotherm Res 146:257–283

    Article  Google Scholar 

  • Jakobsdóttir SS, Guðmundsson GB, Stefánsson R (2002) Seismicity in Iceland 1991–2000 monitored by the SIL seismic system. Jökull 51:87–94

    Google Scholar 

  • Jakobsdóttir SS, Roberts MJ, Guðmundsson GB, Geirsson H, Slunga R (2008) Earthquake swarms at Upptyppingar, North-east Iceland: a sign of magma intrusion? Stud Geophys Geod 52:513–528

    Article  Google Scholar 

  • Kao H, Shan SJ (2004) The source-scanning algorithm: mapping the distribution of seismic sources in time and space. Geophys J Int 157:589–594

    Article  Google Scholar 

  • Klein FW (2002) User’s guide to HYPOINVERSE-2000, a Fortran program to solve for earthquake locations and magnitudes. US Geol Surv Open-file Rep 02–171:1–123

    Google Scholar 

  • Koyanagi RY, Chouet B, Aki K (1987) Origin of volcanic tremor in Hawaii: Part I, Data from the Hawaiian Volcano Observatory, 1969–1985. In: Decker RW, Wright TL, Stauffer PH (eds) Volcanism in Hawaii 2, U.S. Geological Survey Professional Paper 1350 (2), pp 1221–1257

  • Lees JM, Symons N, Chubarova O, Gorelchik V, Ozerov A (2007) Tomographic images of Klyuchevskoy volcano P-wave velocity. AGU Geophysical Monograph 172:293–302

    Google Scholar 

  • McKenzie D, Jackson J, Priestley K (2005) Thermal structure of oceanic and continental lithosphere. Earth Planet Sci Lett 233:337–349

    Article  Google Scholar 

  • McNutt SR (2000) Volcanic seismicity. In: Sigurðsson H (ed) Encyclopedia of volcanoes. Academic Press, San Diego, pp 1015–1033

  • Menke W, Sparks D (1995) Crustal accretion model for Iceland predicts ‘cold’ crust. Geophys Res Lett 22:1673–1676

    Article  Google Scholar 

  • Nakamichi H, Hamaguchi H, Tanaka S, Ueki S, Nishimura T, Hasegawa A (2003) Source mechanisms of deep and intermediate-depth low-frequency earthquakes beneath Iwate volcano, northeastern Japan. Geophys J Int 154:811–828

    Article  Google Scholar 

  • Needleman A, Tvergaard V (2000) Numerical modeling of the ductile-brittle transition. Int J Fracture 101:73–97

    Article  Google Scholar 

  • Neuberg J, Luckett R, Baptie B, Olsen K (2000) Models of tremor and low-frequency earthquake swarms on Montserrat. J Volcanol Geotherm Res 101:83–104

    Article  Google Scholar 

  • Pagli C, Sigmundsson F, Árnadóttir Th, Einarsson P, Sturkell E (2006) Deflation of the Askja volcanic system: constraints on the deformation source from combined inversion of satellite radar interferograms and GPS measurements. J Volcanol Geotherm Res 152:97–108

    Article  Google Scholar 

  • Power JA, Stihler SD, White RA, Moran SC (2004) Observations of deep long-period (DLP) seismic events beneath Aleutian arc volcanoes; 1989–2002. J Volcanol Geotherm Res 138:243–266

    Article  Google Scholar 

  • Sigurðsson H, Sparks SRJ (1978) Lateral magma flow within rifted Icelandic crust. Nature 274:126–130

    Article  Google Scholar 

  • Sigvaldason GE (2002) Volcanic and tectonic processes coinciding with glaciation and crustal rebound: an early Holocene rhyolitic eruption in the Dyngjufjöll volcanic centre and the formation of the Askja caldera, north Iceland. Bull Volcanol 64:192–205. doi:10.1007/s00445-002-0204-7

    Article  Google Scholar 

  • Sigvaldason GE, Annertz K, Nilsson M (1992) Effect of glacier loading/deloading on volcanism: postglacial volcanic production rate of the Dyngjufjöll area, central Iceland. Bull Volcanol 54:385–392

    Article  Google Scholar 

  • Smith KD, von Seggern D, Blewitt G, Preston L, Anderson JG, Wernicke BP, Davis JL (2004) Evidence for deep magma injection beneath Lake Tahoe, Nevada-California. Science 305:1277–1280

    Article  Google Scholar 

  • Soosalu H, Einarsson P (1997) Seismicity around the Hekla and Torfajökull volcanoes, Iceland, during a volcanically quiet period, 1991–1995. Bull Volcanol 59:36–48

    Article  Google Scholar 

  • Soosalu H, Einarsson P (2005) Seismic characteristics of the Hekla volcano and its surroundings, Iceland. Jökull 55:87–106

    Google Scholar 

  • Soosalu H, Einarsson P, Þorbjarnardóttir BS (2005) Seismic activity related to the 2000 eruption of the Hekla volcano, Iceland. Bull Volcanol 68:21–36

    Article  Google Scholar 

  • Sturkell E, Sigmundsson F, Slunga R (2006) 1983–2003 decaying rate of deflation at Askja caldera: pressure decrease in an extensive magma plumbing system at a spreading plate boundary. Bull Volcanol 68:727–735

    Article  Google Scholar 

  • Tuffen H, Dingwell D (2005) Fault textures in volcanic conduits: evidence for seismic trigger mechanisms during silicic eruptions. Bull Volcanol 67:370–387

    Article  Google Scholar 

  • Van der Pluijm B, Marshak S (2004) Earth structure. An introduction to structural geology and tectonics. Norton and Co, New York, pp 1–674

    Google Scholar 

  • Wessel P, Smith WHF (1998) New, improved version of the Generic Mapping Tools released. Eos 79:579

    Article  Google Scholar 

  • Wright TL, Klein FW (2006) Deep magma transport at Kilauea volcano, Hawaii. Lithos 87:50–79

    Article  Google Scholar 

Download references

Acknowledgments

Seismometers loaned from the Natural Environment Research Council SEIS-UK facility were used for fieldwork. The SEIS-UK staff are thanked for assistance during all the phases of the project. E. Sturkell and H. Brynjólfsson provided logistical help and advice. N. Borner, M. Coffin, J. Eccles, K. Harland, D. Hawthorn, J. Hólmjárn, A. Lillington, A. Mikkola, J.-C. Molina Santana, A. Nowacki and S. White participated in the fieldwork. The rangers in the mountain huts of the Askja-Herðubreið nature reserve, and the Akureyri branch of the Icelandic Touring Association are thanked for friendly help in many practical matters. J. Drew helped in data processing and provided the CMM algorithm for earthquake detection. Generic Mapping Tools software (Wessel and Smith 1998) was used for drawing the figures. Comments by S. De Angelis and S. Moran improved the manuscript. Dept. Earth Sciences contribution no. ES.9418.

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Authors and Affiliations

  1. Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge, CB3 0EZ, UK

    Heidi Soosalu, Janet Key, Robert S. White & Clare Knox

  2. Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reyjavík, Iceland

    Páll Einarsson

  3. Icelandic Meteorological Office, Bústaðavegur 9, 150 Reykjavík, Iceland

    Steinunn S. Jakobsdóttir

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  1. Heidi Soosalu
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  2. Janet Key
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  3. Robert S. White
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  4. Clare Knox
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  5. Páll Einarsson
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  6. Steinunn S. Jakobsdóttir
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Correspondence to Heidi Soosalu or Robert S. White.

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Editorial responsibility: M. Ripepe

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Soosalu, H., Key, J., White, R.S. et al. Lower-crustal earthquakes caused by magma movement beneath Askja volcano on the north Iceland rift. Bull Volcanol 72, 55–62 (2010). https://doi.org/10.1007/s00445-009-0297-3

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