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Broad accommodation of rift-related extension recorded by dyke intrusion in Saudi Arabia


The extensive harrat lava province of Arabia formed during the past 30 million years in response to Red Sea rifting and mantle upwelling. The area was regarded as seismically quiet, but between April and June 2009 a swarm of more than 30,000 earthquakes struck one of the lava fields in the province, Harrat Lunayyir, northwest Saudi Arabia. Concerned that larger damaging earthquakes might occur, the Saudi Arabian government evacuated 40,000 people from the region. Here we use geologic, geodetic and seismic data to show that the earthquake swarm resulted from magmatic dyke intrusion. We document a surface fault rupture that is 8 km long with 91 cm of offset. Surface deformation is best modelled by the shallow intrusion of a north-west trending dyke that is about 10 km long. Seismic waves generated during the earthquakes exhibit overlapping very low- and high-frequency components. We interpret the low frequencies to represent intrusion of magma and the high frequencies to represent fracturing of the crystalline basement rocks. Rather than extension being accommodated entirely by the central Red Sea rift axis, we suggest that the broad deformation observed in Harrat Lunayyir indicates that rift margins can remain as active sites of extension throughout rifting. Our analyses allowed us to forecast the likelihood of a future eruption or large earthquake in the region and informed the decisions made by the Saudi Arabian government to return the evacuees.

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Figure 1: Index map, showing the 180,000 km2 harrat lava fields (black) within Saudi Arabia.
Figure 2: Digital helicorder records for 19 May 2009 from seismic station LNYS (located 15 km SE of the fault rupture).
Figure 3: Ten-minute real-time seismic amplitude (RSAM) plots showing peak seismic energy release for the vertical component of broadband seismic stations UMJS and LNYS (45 km WSW and 29 km SE from the epicentre of the M5.4 earthquake).
Figure 4: Photographs showing the surface rupture produced by the 19 May 2009 earthquake.
Figure 5: Images showing seismic and deformation data from 2009 activity at Harrat Lunayyir.
Figure 6: Oblique aerial photograph showing basalt cinder cones and lava in northern Harrat Lunayyir.


  1. Ambraseys, N. N. & Melville, C. P. Evidence for intraplate earthquakes in northwest Arabia. Bull. Seismol. Soc. Am. 79, 1279–1281 (1989).

    Google Scholar 

  2. Ambraseys, N. N. Reassessment of earthquakes, 1900–1999, in the Eastern Mediterranean and the Middle East. Geophys. J. Int. 145, 471–485 (2001).

    Article  Google Scholar 

  3. Camp, V. E., Hooper, P. R., Roobol, M. J. & White, D. L. The Madinah eruption, Saudi Arabia: Magma mixing and simultaneous eruption of three basaltic chemical types. Bull. Volcanol. 49, 489–508 (1987).

    Article  Google Scholar 

  4. Moufti, M. R. H. The Geology of Harrat Al-Madinah Volcanic Field, Harrat Rahat, Saudi Arabia. 465, PhD thesis, Univ. Lancaster, England (1985).

  5. Van Padang, N. M. Catalogue of the Active Volcanoes of the World, Including Solfatara Fields of Arabia and Indian Ocean, Vol. 16 1–64 (Int. Assoc. Volcanol., 1963).

    Google Scholar 

  6. Roobol, M. J. Geology, Structure and Seismicity of Harrat Lunayyir Volcanic Field. Al-Eis region, northwestern Saudi Arabia. Saudi Geol. Surv. Rep. 14 (2009).

  7. Al Amri, A. M. S. Recent seismic activity in the northern Red Sea. J. Geodyn. 20, 243–253 (1995).

    Article  Google Scholar 

  8. El Isa, Z. H. & Al Shanti, A. Seismicity and tectonics of the Red Sea and western Arabia. Geophys. J 97, 449–457 (1989).

    Article  Google Scholar 

  9. Camp, V. E. & Roobol, M. J. The Arabian continental alkali basalt province: Part I. Evolution of Harrat Rahat, Kingdom of Saudi Arabia. Geol. Soc. Am. Bull. 101, 71–95 (1989).

    Article  Google Scholar 

  10. Camp, V. E., Roobol, M. J. & Hooper, P. R. The Arabian continental alkali basalt province: Part II. Evolution of Harrats Khaybar, Ithnayn, and Kura, Kingdom of Saudi Arabia. Geol. Soc. Am. Bull. 103, 363–391 (1991).

    Article  Google Scholar 

  11. Murray, T. L. & Endo, E. T. A real-time seismic-amplitude measurement system (RSAM). US Geol. Surv. Bull. 1966, 5–10 (1992).

    Google Scholar 

  12. Hill, D. P. et al. The 1989 earthquake swarm beneath Mammoth Mountain, California; an initial look at the 4 May through 30 September activity. Bull. Seismol. Soc. Am. 80, 325–339 (1990).

    Google Scholar 

  13. Lahr, J. C., Chouet, B. A., Stephens, C. D., Power, J. A. & Page, R. A. Earthquake classification, location, and error analysis in a volcanic environment: Implications for the magmatic system of the 1989–1990 eruptions at Redoubt Volcano. J. Volcanol. Geotherm. Res. 62, 137–151 (1994).

    Article  Google Scholar 

  14. McNutt, S. R. in Monitoring and Mitigation of Volcano Hazards (eds Scarpa, R. & Tilling, R. I.) 99–196 (Springer, 1996).

    Book  Google Scholar 

  15. Jacobs, K. M. & McNutt, in The 2006 Eruption of Augustine Volcano, Alaska (eds Power, J. A., Coombs, M. L. & Freymueller, J. T.) (US Geological Survey Professional Paper, (1769, in the press).

  16. Ohminato, T., Chouet, B. A., Dawson, P. & Kedar, P. Waveform inversion of very long period impulsive signals associated with magmatic injection beneath Kilauea Volcano, Hawaii. J. Geophys. Res. 103, 23839–23862 (1998).

    Article  Google Scholar 

  17. Chouet, B. A. Volcano seismology. Pure Appl. Geophys. 160, 739–788 (2003).

    Article  Google Scholar 

  18. McNutt, S. R. Volcano Seismology. Annu. Rev. Earth Planet. Sci. 33, 461–491 (2005).

    Article  Google Scholar 

  19. Dowrick, D. W. & Rhodes, D. A. Relations between earthquake magnitude and rupture dimensions. How regionally variable are they? Bull. Seismol. Soc. Am. 94, 776–788 (2004).

    Article  Google Scholar 

  20. Hanks, T. C. & Kanamori, H. A moment magnitude scale. J. Geophys. Res. 84, 2348–2350 (1979).

    Article  Google Scholar 

  21. Calais, E. et al. Strain accomodation by slow slip and dyking in a youthful continental rift, East Africa. Nature 456, 783–787 (2008).

    Article  Google Scholar 

  22. Wright, T. J. et al. Magma-maintained rift segmentation at continental rupture in the 2005 Afar dyking episode. Nature 442, 291–294 (2006).

    Article  Google Scholar 

  23. Kanamori, H. & Given, J. W. Use of long-period surface waves for rapid determination of earthquake source parameters. Phys. Earth Planet. Inter. 27, 8–31 (1981).

    Article  Google Scholar 

  24. Zobin, V. M. Seismic hazard of volcanic activity. J. Volcanol. Geotherm. Res. 112, 1–14 (2001).

    Article  Google Scholar 

  25. Parsons, T. & Thompson, G. A. The role of magma overpressure in suppressing earthquakes and topography: Worldwide examples. Science 253, 1399–1402 (1991).

    Article  Google Scholar 

  26. Ebinger, C. et al. Length and timescales of rift faulting and magma intrusion: The Afar rifting cycle from 2005 to present. Annu. Rev. Earth Planet. Sci. 38, 439–466 (2010).

    Article  Google Scholar 

  27. Keir, D. et al. Evidence for focused magmatic accretion at segment centres from lateral dike injections captured beneath the Red Sea rift in Afar. Geology 37, 59–62 (2009).

    Article  Google Scholar 

  28. Girdler, R. & Styles, P. Two-stage Red Sea floor spreading. Nature 247, 7–11 (1974).

    Article  Google Scholar 

  29. Pallister, J. S. Magmatic history of Red Sea rifting. Geol. Soc. Am. Bull. 98, 400–417 (1987).

    Article  Google Scholar 

  30. Bohannon, R. G. Tectonic configuration of the western Arabian continental margin, southern Red Sea. Tectonics 5, 477–499 (1986).

    Article  Google Scholar 

  31. Bohannon, R. G., Naeser, C. W., Schmidt, D. L. & Zimmermann, R. A. The timing of uplift, volcanics, and rifting peripheral to the Red Sea: A case for passive rifting? J. Geophys. Res. 94, 1683–1701 (1989).

    Article  Google Scholar 

  32. Coleman, R. G. & McGuire, A. V. Magma systems related to the Red Sea opening. Tectonophysics 150, 77–100 (1988).

    Article  Google Scholar 

  33. Cochran, J. R. A model for the development of the Red Sea. Am. Assoc. Petrol. Geol. Bull. 67, 41–69 (1983).

    Google Scholar 

  34. Steckler, M. S. Uplift and extension at the Gulf of Suez—indications of induced mantle convection. Nature 317, 135–139 (1985).

    Article  Google Scholar 

  35. LeTourneau, P. M. & Olsen, P. E. The Great Rift Valleys of Pangea in Eastern North America, Tectonics, Structure, and Volcanism (Colombia Univ. Press, 2003).

    Book  Google Scholar 

  36. Coleman, R. G., Gregory, R. T. & Brown, G. F. Cenozoic Volcanic Rocks of Saudi Arabia. US Geol. Surv. Open-file Rep. 83–788 and Saudi Arabian Deputy Minist. Miner. Resour., Open File Rep. USGS-OF-03-93 (1983).

  37. Camp, V. E. & Roobol, M. J. Upwelling asthenosphere beneath western Arabia and its regional implications. J. Geophys. Res. 97, 15255–15271 (1992).

    Article  Google Scholar 

  38. Al-Saud, M. M. Seismic characteristics and kinematic models of Makkah and central Red Sea regions. Arab. J. Geosci. 1, 49–61 (2008).

    Article  Google Scholar 

  39. Hansen, S., Schwartz, S., Al-Amri, A. & Rogers, A. Combined plate motion and density-driven flow in the asthenosphere beneath Saudi Arabia: Evidence from shear-wave splitting and seismic anisotropy. Geology 34, 869–872 (2006).

    Article  Google Scholar 

  40. McClusky, S. et al. Global positioning system constraints on plate kinematics and dynamics in the Eastern Mediterranean and Caucasus. J. Geophys. Res. 105, 5695–5719 (2000).

    Article  Google Scholar 

  41. McClusky, S., Reilinger, R., Mahmoud, S., Ben Sari, D. & Tealeb, A. GPS constraints of Africa (Nubia) and Arabia plate motions. Geophys. J. Int. 155, 126–138 (2003).

    Article  Google Scholar 

  42. Johnson, P. R. Proterozoic Geology of Western Saudi Arabia, North-Central Sheet. Saudi Geol. Surv. Open-file Rep. SGS-OF-2005-5, 1:500,000 map (2005).

  43. Johnson, P. R. Explanatory Notes to the Map of Proterozoic Geology of Western Saudi Arabia. Saudi Geol. Surv. Tech. Rep. SGS-TR-2006-4, 1:500,000 map (2006).

  44. Zahran, H. M., Stewart, I. C. F., Johnson, P. R. & Basahel, M. H. Aeromagnetic-Anomaly Maps of Central and Western Saudi Arabia. Saudi Geol. Surv. Open-file Rep. SGS-OF-2002-8, scale 1:2,000,000 (2002).

  45. Hansen, S. E., Rodgers, A. J., Schwartz, S. Y. & Am-Amri, A. M. S. Imaging ruptured lithosphere beneath the Red Sea and Arabian Peninsula. Earth Planet. Sci. Lett. 259, 256–265 (2007).

    Article  Google Scholar 

  46. Smithsonian-Institution. Jebel at Tair. Bull. Global Volc. Pgm. 32 (10) (2007).

  47. Baker, P. E., Brosset, R., Gass, I. G. & Neary, C. R. Jebel al Abyad: A recent alkalic volcanic complex in western Saudi Arabia. Lithos 6, 291–314 (1973).

    Article  Google Scholar 

  48. Okada, Y. Internal deformation due to shear and tensile faults in a half-space. Bull. Seismol. Soc. Am. 82, 1018–1040 (1992).

    Google Scholar 

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This work is the result of a joint effort of the Saudi Arabian Geological Survey (SGS), and the US Geological Survey (USGS), conducted with the assistance of the US Consulate, Jeddah, Saudi Arabia. We thank many SGS colleagues (too numerous to list individually here) who participated in field and laboratory work and contributed to the success of the crisis response. We also acknowledge support to the Volcano Disaster Assistance Program provided by USAID’s Office of Foreign Disaster Assistance and the USGS Volcano Hazards Program, and we thank SGS President Z. Nawab for facilitating our work together. Original Envisat radar raw data are copyrighted by the European Space Agency (ESA) and were provided by ESA. We also acknowledge the Nature Geoscience reviewers and editor Whitchurch, whose contributions substantially improved this paper.

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Authors and Affiliations



H.M.Z. organized the overall crisis response and coordinated the results with government officials. S.E.H. contributed earthquake focal solutions and seismic data. A.A. provided computer programming and seismic network data support. I.C.F.S. contributed to the geophysics and field geology, seismic location interpretations, and overall communication between the groups. W.A.M. analysed and interpreted all of the continuous seismic data. Z.L. processed and interpreted Envisat data, S.J. modelled and interpreted the radar data, P.R.L. processed and interpreted Terra-SAR-X data, J.S.P. conducted field work, contributed to volcanic hazards analysis and with assistance from W.A.M. and S.J., wrote the paper. R.A.W. summarized data on comparable seismic swarms and magnitudes from other volcanic fields for use in forecasting. M.R.H.M. contributed volcanologic data and context based on his extensive field work on the harrat fields of Saudi Arabia.

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Correspondence to John S. Pallister.

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Pallister, J., McCausland, W., Jónsson, S. et al. Broad accommodation of rift-related extension recorded by dyke intrusion in Saudi Arabia. Nature Geosci 3, 705–712 (2010).

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