### Volcano hazards from Mount Rainier, Washington, revised 1998

By: R. P. HoblittJ. S. WilderC. L. DriedgerK. M. ScottP. T. PringleJ.W. Vallance

                            https://doi.org/10.3133/ofr98428

#### Links

- More information:  **USGS Index Page**                            (html)
-                                                                                                                             Document:                                                                                                                                                                                                                                                  **Report**                                                                                                     (pdf)                                                                                                                                     
- Plates:                               - **Plate 1**                            (pdf)
  - **Plate 2**                            (pdf) 
- NGMDB Index Page:  **National Geologic Map Database Index Page**                            (html)
- Download citation as:  RIS                         |                         Dublin                            Core

#### Abstract

Mount Rainier—at 4393 meters (14,410 feet) the highest peak in the Cascade Range—is a dormant volcano whose load of glacier ice exceeds that of any other mountain in the conterminous United States. This tremendous mass of rock and ice, in combination with great topographic relief, poses a variety of geologic hazards, both during inevitable future eruptions and during the intervening periods of repose.

The volcano’s past behavior is the best guide to possible future hazards. The written history of Mount Rainier encompasses the period since about A.D. 1820, during which time one or two small eruptions, several small debris avalanches, and many small lahars (debris flows originating on a volcano) have occurred. This time interval is far too brief to serve as a basis for estimating the future behavior of a volcano that is several hundreds of thousands of years old. Fortunately, prehistoric deposits record the types, magnitudes, and frequencies of past events, and show which areas were affected by them. At Mount Rainier, as at other Cascade volcanoes, deposits produced since the latest ice age (approximately during the past 10,000 years) are well preserved. Studies of these deposits reveal that we should anticipate potential hazards from some phenomena that only occur during eruptions and from others that may occur without eruptive activity. Tephra falls, pyroclastic flows and pyroclastic surges, ballistic projectiles, and lava flows occur only during eruptions. Debris avalanches, lahars, and floods commonly accompany eruptions, but can also occur during dormant periods.

This report (1) explains the various types of hazardous geologic phenomena that could occur at Mount Rainier, (2) shows areas that are most likely to be affected by the different phenomena, (3) estimates the likelihood that the areas will be affected, and (4) recommends actions that can be taken to protect lives and property. It builds upon and revises a similar document prepared by D.R. Crandell in 1973. Our revision was motivated by the availability of new information about Mount Rainier’s geologic history, by advances in the field of volcanology, and by the need to assess hazards in a more quantitative manner than in Crandell’s pioneering report.

#### Study Area

Part or all of this report is presented in Portable Document Format                        (PDF). For best results viewing and printing PDF documents, it is recommended that you download                        the documents to your computer and open them with Adobe Reader. PDF documents opened from your                        browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge. More information                        about viewing, downloading, and printing report files can be found at the common download problems FAQ.