Volume 17, Number 3 (1990)

Patterns of Volcanism in the Cascade Arc During the Past 15,000 Years

William E. Scott
David A Johnston Cascades Volcano, Observatory, United States Geological Survey, Vancouver, Washington.

Published 1990-09-09

How to Cite

Scott, W. E. (1990). Patterns of Volcanism in the Cascade Arc During the Past 15,000 Years. Geoscience Canada, 17(3). Retrieved from https://journals.lib.unb.ca/index.php/GC/article/view/3675


About 110 well-dated and 70 poorly dated eruptive periods less than 15,000 years old at individual volcanoes in the Cascade arc constitute a data set for identifying spatial and temporal patterns of eruptive activity. Key features of the record include: (1) the mean frequency of eruptive periods during the past 4,000 years is approximately two per century, however, the variance about the mean may be large; (2) at most major centres, episodes of activity lasting several thousand years are defined by groups of eruptive periods separated by apparent dormant intervals of roughly similar duration, (3) arc-wide clustering of eruptive activity may exist at 0-4 ka, 6-8 ka, and 10-14 ka. Such clustering would be remarkable in light of significant along-arc changes in crustal structure, stress field, and subduction-zone geometry.