Miscellaneous Field Studies Map 786
Volcanic eruptions and related phenomena can be expected to occur in the Western United States, and in some places are potentially hazardous enough to be considered in longe-range land-use planning. But the immediate risk from volcanic hazards is low because eruptions are so infrequent in the conterminous United States that few, if any, occur during any one person's lifetime. Furthermore, severely destructive effects of eruptions, other than extremely rare ones of catastrophic scale, probably would be limited to areas within a few tens of kilometers downvalley or downwind from a volcano. Thus, the area seriously endangered by any one eruption would be only a very small part of the Western United States.
The accompanying map identifies areas in which volcanic hazards pose some degree of risk, and shows that the problem is virtually limited to the far western States. The map also shows the possible areal distribution of several kinds of dangerous eruptive events and indicates the relative likelihood of their occurrence at various volcanoes. The kinds of events described here as hazards are those that can occur suddenly and with little or no warning; they do not include long-term geologic processes. Table 1 summarizes the origin and some characteristics of potentially hazardous volcanic phenomena.
The map is diagrammatic. It does not show the specific location of the next expected eruption , because such an event cannot be reliably predicted . Instead, the map shows general areas or zones that, over a long period of time, are relatively likely to be affected in one or more places by various kinds of hazardous volcanic events. However, only a small part of one of these areas would be affected by any single eruption.
For additional information, contact:
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.
Mullineaux, D. R., 1976, Preliminary overview map of volcanic hazards in the 48 conterminous United States: U.S. Geological Survey Miscellaneous Field Studies Map 786, https://pubs.usgs.gov/mf/0786/.