SEATTLE — The University of Washington’s Pacific Northwest Seismic Network (PNSN) will present “Mount St. Helens and the Cascade Range Volcanoes: The 40th Anniversary Program” from 6:30 p.m. to 8 p.m. Monday.

The free program features a review of the Cascadia region’s tectonics, volcanoes and volcanic hazards as well as a discussion of the evolution of the science and monitoring of volcanoes has evolved over the past 40 years.

University of Washington seismologist Steve Malone will also provide a first-person account of the buildup to the eruption on May 18, 1980.

Other presenters include Harold Tobin, director of the PNSN; Jackie Caplan-Auerbach, a professor of geophysics at Western Washington University; Josef Dufek, a professor of volcanology at the University of Oregon; and Seth Moran, of the U.S. Geological Survey’s Cascade Volcano Observatory.

The webinar will stream on the network’s YouTube channel at www.youtube.com/user/pnseisinfo.

The program will be followed by a live Q&A session on the network’s facebook page at www.facebook.com/thepnsn.

Mount St. Helens is 145 miles south of Port Angeles.