REVISITING THE 1975 PHREATIC ACTIVITY AT MOUNT BAKER, AND PUBLIC PERCEPTIONS OF VOLCANIC HAZARDS

In March of 1975, elevated thermal activity at Mount Baker, Washington state, melted off a large amount of glacial ice in the Sherman Crater area, south of the main summit. A previously active fumarole system was found to have increased in size and magnitude. Closer inspection of Sherman Crater also revealed large amounts of hydrothermally altered material prompting concern for debris avalanches and causing the closure of Baker Lake tourist areas. Although it did not erupt, Baker has never returned to pre-1975 levels of activity. In order to explain the 1975-1976 activity, this study outlined four possible sources of the thermal events, including a non-magmatic source and discussed the likelihood of each one. A current review of studies conducted both during the thermal event in 1975-1976 and since has presented the possibility that thermal activity was instigated by magmatic activity. Certain studies have identified magmatic gases present in the gaseous plume from Mount Baker.

Besides the review of volcanic activity at Mount Baker, this study also reviewed community awareness in the surrounding small communities. Many people use the Baker wilderness year-round, causing concern that visitors may be unaware of volcanic hazards related to Mount Baker. Therefore this project has, in part, attempted to assess community awareness of volcano hazards related to Mount Baker. The goal is to identify levels of understanding and any misconceptions held by nearby residents to better prepare a future hazards awareness campaign in these communities. A questionnaire was created to ask where people travel and what they do around the volcano, thus helping identify where volcanic hazard information can be provided. Also, it asked what hazards people believe will affect their community and what they know of volcanoes and their impacts. Identification of misconceptions may allow public education efforts to better prepare the public to coexist with Mount Baker and volcanic activity.