Photographic archive collection from the USGS Photo Library. Photos dated 1868-1992 are of geology, earthquake damage, national parks, pioneer photographers, St. Helens eruption and mining and available at 100, 700 and 1400 dots/inch resolution.
Article in the May 28, 1998 issue of Volcano Watch describing of correlation of earth tides to volcanic eruptions and value in monitoring underground magma movement with deformation measurement instruments including tiltmeters and strainmeters.
Of 129 reported incidents, 94 are confirmed ash encounters, 79 of which entailed airframe or engine damage; 20 are low-severity events involving suspected ash or gas clouds; for 15 the data are insufficient to assess severity.
Describes strategy of volcano warnings and the real-time detection of a sudden eruption or lahar and immediate notification of the activity to the public and local, state, and federal emergency-management officials.