Unique and remarkable dilatometer measurements of pyroclastic flow–generated tsunamis
- G.S. Mattioli1,
- B. Voight2,
- A.T. Linde3,
- I.S. Sacks3,
- P. Watts4,
- C. Widiwijayanti5,
- S.R. Young5,
- D. Hidayat5,
- D. Elsworth5,
- P.E. Malin6,
- E. Shalev6,
- E. Van Boskirk7,
- W. Johnston7,
- R.S.J. Sparks8,
- J. Neuberg9,
- V. Bass10,
- P. Dunkley10,
- R. Herd10,
- T. Syers10,
- P. Williams10 and
- D. Williams10
- 1University of Arkansas, Fayetteville, Arkansas 72701, USA
- 2Pennsylvania State University, University Park, Pennsylvania 16802, USA
- 3Carnegie Institution of Washington, 530 P Street NW, Washington, D.C. 20005, USA
- 4Applied Fluids Engineering, Inc., 5710 E 7th St. #237, Long Beach, California 90803, USA
- 5Pennsylvania State University, University Park, Pennsylvania 16802, USA
- 6Duke University, Durham, North Carolina 27708, USA
- 7University of Arkansas, Fayetteville, Arkansas 72701, USA
- 8University of Bristol, Tyndall Avenue, Bristol BS8 1TH, UK
- 9University of Leeds, Leeds LS2 9JT, UK
- 10Montserrat Volcano Observatory, Salem, Montserrat, West Indies
Abstract
Pyroclastic flows entering the sea may cause tsunamis at coastal volcanoes worldwide, but geophysically monitored field occurrences are rare. We document the process of tsunami generation during a prolonged gigantic collapse of the Soufrière Hills volcano lava dome on Montserrat on 12–13 July 2003. Tsunamis were initiated by large-volume pyroclastic flows entering the ocean. We reconstruct the collapse from seismic records and report unique and remarkable borehole dilatometer observations, which recorded clearly the passage of wave packets at periods of 250–500 s over several hours. Strain signals are consistent in period and amplitude with water loading from passing tsunamis; each wave packet can be correlated with individual pyroclastic flow packages recorded by seismic data, proving that multiple tsunamis were initiated by pyroclastic flows. Any volcano within a few kilometers of water and capable of generating hot pyroclastic flows or cold debris flows with volumes greater than 5 × 106 m3 may generate significant and possibly damaging tsunamis during future eruptions.
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- Received 25 April 2006.
- Accepted 11 August 2006.
- Revision received 3 August 2006.
- Geological Society of America












