L K Queen, C J Nye (AVO./ADGGS, 794 Univ. Ave. #200, Fairbanks, AK 99709; email: kathie@dnr.state.ak.us); J P Benoit, K G Dean, K Engle, K G Lindquist, M S Servilla (all at AVO/UAFGI, Fairbanks, AK 99775-7320); W R Hammond (AVO/USGS, c/o UAFGI, Fairbanks, AK 99775-7320)

The Alaska Volcano Observatory (AVO) uses an internal World Wide Web internet site as an essential part of its volcano monitoring program. The top page contains links to near-real-time seismic, satellite, and weather data as well as interactive log sheets and calendars. The page permits rapid distribution of diverse data between AVO’s geographically distributed offices as well as off-site monitoring using home computers and modems. The latter feature is especially useful during protracted periods of around-the-clock monitoring.

Seismic data include plots of Real-time Seismic Amplitude Measurement (RSAM), spectrograms, reduced displacement, and synthetic helicorder traces. All these are automatically written every few minutes to graphics files viewable by common web browsers. Together, the plots permit detailed inspection of many facets of the seismicity, such as unfiltered and filtered amplitudes and frequency contents of the signals. The seismic displays make use of multiple hardware and software paths including PC Willie systems and the Unix-based automated seismic data processing package, ICEWORM, and Matlab.

AVHRR satellite images are geometrically and radiometrically corrected, subsectioned, and the contrast is enhanced and a coastline embedded. GIF images of each file are posted. The subsectioning allows full-resolution image files small enough to be retrieved over modems. These processing techniques are automated and the images are available for viewing within 10 minutes of each satellite pass. Images of bands 2, 3, 4, and 4 minus 5 (useful for detecting volcanic ash) are produced for seven subsections of each of about 20 passes per day. The most recent images are posted, and a two-day archive preserved. NWS weather data, which aid in understanding seismic signals (e.g. ground-shaking by storms) and interpreting pilot and remote observer reports, are linked to the page. In addition the page is linked to automatically-generated output of the ash-plume dispersal model, PUFF.

Perl scripts are used to generate a log sheet of comments made by remote observers and an interactive calendar used for coordinating volcano watch duty. These scripts permit observations to be scheduled, reported, and discussed from diverse locations using standard web browsers.

Planned additions and improvements are legion.

The Alaska Volcano Observatory is a cooperative program of the US Geological Survey, UAF Geophysical Institute, and Alaska Division of Geological and Geophysical Surveys.