Peter L. Ward

Seismic evidence for magma in the vicinity of Mt. Katmai, Alaska

P-wave traveltime delays of as much as 0.9 sec are consistently observed at one seismic station from local and regional earthquakes 70 to 150 km deep. This station is on the southwest flank of Mt. Trident, the most recently active volcano within Katmai National Park, Alaska. Delays from local shallow earthquakes are typically less than 0.3 sec, suggesting that most of the major delay results from anomalous material at depths of more than a few kilometers. This station is located near the center of a bowlshaped low in the Bouguer gravity field that is approximately 15 km in diameter and more than 25 mgals deep. These anomalies suggest, but do not prove, the presence of considerable amounts of magma in the shallow part of the crust that could have been the source for all magma erupted in the vicinity of Mt. Katmai and Mt. Trident this century.

SUDS: The seismic unified data system

Our ability to collect high-quality digital data is increasing much more rapidly than our ability to process it. This is partly due to the revolution in digital technology and partly to increased teamwork in building equipment and carrying out major projects such as those fostered in seismology by the IRIS Consortium (Incorporated Research Institutions for Seismology). The need is now great for a similar level of teamwork in data processing. The Seismic Unified Data System (SUDS) is a foundation suitable for such teamwork in all types of seismic processing, from studies of earthquakes to discrimination of explosions to reflection and refraction studies.

Global data collection and the surveillance of active volcanoes

Abstract Data relay systems on existing earth-orbiting satellites provide an inexpensive way to collect environmental data from numerous remote sites around the world. This technology could be used effectively for fundamental monitoring of most of the worlds active volcanoes. Such global monitoring would focus attention on the most dangerous volcanoes that are likely to significantly impact the geosphere and the biosphere.