Volcanic activity resumed at Mt. St. Helens on March 20, 1980, after 123 years of quiet. Over a period of five days, the threat of a major eruption increased and subsided. Media coverage of the volcano was initially intense, but gradually declined and nearly disappeared by the second week of May (Earle, Southwick and Lindell 1981). In addition to fluctuations in the severity of the threat, there were uncertainties about the areas at greatest risk. During the initial emergency period, the Lewis River Valley on the south side of the mountain was thought likely to be the area of most severe impacts. Later the formation of a bulge on the northwest side of the volcano diverted attention to the Toutle River Valley, which ultimately bore the brunt of the catastrophic explosion on May 18th. Since that time, steam, ash and effusive (dome building) eruptions have decreased, although the threat of flooding caused by ash deposition in the river continued until the very recent completion of a sediment retention dam (Perry and Lindell 1990a).
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Risk Area Residents’ Changing Perceptions of Volcano Hazard AT MT. ST. Helens
Michael K. Lindell
Ronald W. Perry
- Springer Netherlands