A comparison of seismic event detection with IASPEI and earthworm acquisition systems at Alaskan volcanoes

Since 1988, Alaska Volcano Observatory (AVO) has been continually monitoring seismicity at active volcanoes in Alaska (Dixon et al., 2004). The AVO seismic network has grown from 27 stations on the Cook Inlet volcanoes (Augustine, Iliamna, Redoubt, and Spurr) to 160 stations on 27 volcanoes in 2004 (Figure 1). Each seismograph subnetwork on an individual volcano typically consists of five short-period vertical stations and one short-period three-component station surrounding the volcanic center at distances of 1 to 20 km. The configuration of each subnetwork varies depending on numerous factors such as local topography, available telemetry options, and the grouping of individual volcanic centers. Historically, the AVO seismic network has used short-period geophones and standard analog telemetry because of reliability, cost, and availability. As telemetry bandwidth has become more readily available, AVO has begun to deploy broadband seismometers and digital communications for telemetry (Murray et al., 2002).