Seismic Explorations in the Eastern Aleutians, Alaska

Abstract

In the summer of 2001 two groups from the Alaska Volcano Observatory (AVO) deployed temporary seismic stations in two areas on Umnak Island, Alaska (Figure 1). For AVO, such deployments are the exception rather than the rule. AVO operates a real-time seismic network of 135 stations on 25 of the 40+ historically active volcanoes in Alaska (Dixon et al. , 2002), spanning a distance of just less than 2,300 km (Figure 1). This span encompasses one of the most volcanically and seismically active arcs in the world. AVO's traditional emphasis has been to study seismicity associated with volcanic processes through installation of permanent real-time seismic networks and analysis of the resultant signals from its laboratories in Anchorage and Fairbanks. Little emphasis has been placed on temporary deployments, for three reasons: (1) AVO's mission-critical goal is to provide near-real-time assessments of volcanic activity in Alaska, a goal not readily served by temporary deployments because of the time required for their deployment and because data from such deployments are often stored on-site and are thus not available for real-time monitoring; (2) logistical considerations (travel and shipping expenses, marginal weather, etc.) place limits on where and when specialized studies can be performed; and (3) AVO has been reluctant to devote resources to establishing and maintaining a cache of instruments dedicated to rapid response, preferring instead to maximize the number of stations deployed permanently in the field. Thus the two temporary deployments in 2001 were a significant departure from AVO's normal mode of operations and as such represented a test of whether targeted temporary deployments have a place in the routine operations of the observatory. The results not only relate to AVO's operation and mission, but could be relevant to other observatories and research groups, particularly those investigating remote or understudied volcanoes. The two …