Los Alamos Women in Science
Northern Chapter of the New Mexico Network for Women in Science and Engineering
sponsored by
the   Synergy Center  ,   the   Zocher Corporation
and the Bradbury Science Museum
Talk at 12:00, Wednesday, February 9, 2005
Bldg 1, Los Alamos Research Park
Synergy Center Conference Room, 3rd flr

Soufriere Hills volcano in the background with the ash-covered city of Plymouth (former capital of Montserrat) in the foreground.

Charlotte A. Rowe, EES-11, LANL
From Montserrat
to Mount St. Helens:
Seismic insights into ongoing
volcanic eruption behavior

Volcanic eruptions take on many forms and styles; among those which require the greatest vigilance are the silicic types of volcanoes whose eruption behavior may be characterized by extended periods (months or years) of repeated extrusive and explosive activity. Gauging the level of hazard for such volcanoes is an ongoing task, and the ability to ascertain the degree of danger may have profound social and economic impacts on the nearby population. Soufriere Hills volcano, Montserrat, began erupting in 1995 and continues today. We have relocated a subset of events from the digital waveform catalogue of ~17,000 volcanic microearthquakes recorded between July 1995 and February 1996, using a cross-correlation-based phase repicking technique with a joint location method. Relocated events represent 36 swarms, each containing nearly identical waveforms, having source dimensions of 10 to 100 m in diameter and spatial separations on the order of 500 m or less. Each swarm occurred over a span of several hours to a few days. Visual estimates of summit dome growth show a rough correspondence between episodes of intense seismic swarming and increases in extruded magma, although dome observations are too sparse to make a direct comparison for this time period. A better understanding of the seismicity and how it relates to the mechanics of dome growth may lead to insights into likely behavior in the short term, and the ability to assess magma extrusion rates in the absence of visual or geodetic information. Similar behavior at Mount St. Helens recently led to a media blitz and elevated levels of public angst regarding a renewal of activity, perhaps akin to that experienced in 1980. Continued surveillance and exploration of the connection between seismic behavior and eruption scenarios may help to moderate the potential for over-reaction to potentially dangerous volcanoes; however, the risk of understating the threat cannot be ignored. We strive to improve our understanding for timely and accurate evaluation of the hazard as eruptions evolve. (work done with C.H. Thurber and R.A. White, LA-UR-05-0482)

Members and Nonmembers Welcome!
Open to the Public