Volcanism and Volcanic Hazards at Lassen Peak and Crater Lake

BILL HIRT, College of the Siskiyous

July 23-26, 2007 in Weed, CA and Lassen & Crater Lake National Parks Apply: UWA

Note: This course has a participant fee of $100 (in addition to the application fee) to cover the costs of van transportation and lunches during the course.

Northern California and southern Oregon are natural laboratories for studying volcanic activity and its potential hazards in the Cascade Range. The region is home to Lassen Volcanic National Park and Crater Lake National Park, which preserve landscapes shaped by recent volcanism of contrasting styles. The demise of both Mount Tehama and Mount Mazama (one with a whimper, the other with a bang) presents a fascinating study in contrasts, and offers insights into what may lie ahead for the towering snow-clad peaks that dominate the Cascade Range today. The hot springs and fumaroles of Lassen Volcanic National Park belie an active magmatic system beneath Lassen Peak, which last erupted in 1917. All of these features lie within the footprint of Mount Tehama, an 11,000 foot stratovolcano that dominated the area about 610,000 years ago. This massive peak succumbed slowly to erosion as hot acidic water “rotted” its interior and streams and glaciers carved away the softened rock. Today, lava flows that snaked down Mount Tehama’s flanks point skyward towards its missing summit and remind us of the impermanence of even massive volcanic peaks in the face of alteration and gravity.

The centerpiece of Crater Lake National Park is the 10 km wide caldera that marks where the summit of Mount Mazama stood until 7,700 years ago. Unlike Mount Tehama, this volcano was destroyed in a matter of days when massive eruptions from a shallow magma reservoir undermined its upper slopes and led to collapse. Although there is little hydrothermal activity on the floor of the lake that fills the caldera today, deposits on the volcano’s flanks tell of a climactic eruption that burned and buried forests tens of kilometers from the peak. Although large caldera-forming eruptions are rare in the Cascades, their violence makes them an awesome threat.

This four-day program will include day trips to Lassen and Crater Lake National Parks so that participants can study the landforms and eruptive products unique to each volcano. In addition, two days of classroom discussions and laboratory sessions at College of the Siskiyous will introduce the tectonic setting and geologic processes that are shaping the southern Cascades, review how volcanic hazards are being monitored and assessed in this region, and acquaint participants with materials and activities that they can use to facilitate student learning about volcanism and volcanic hazards in their own classrooms. .

For college teachers of: all disciplines, but particularly natural sciences and social sciences. Prerequisites: none. Limit: 20 participants

Dr. Hirt is a geology instructor in the Division of Natural and Applied Sciences at College of the Siskiyous. He has 18 years experience teaching a wide variety of earth-science courses – from igneous petrology and mineralogy to general and regional geology – in both academic and popular settings. His research is directed towards better understanding the thermal and compositional changes that felsic magmas undergo as they traverse the crust, and is currently focused on studies in California’s Sierra Nevada and southwestern Idaho’s Bruneau-Jarbidge Eruptive Center.

Course Outline

Prior to July 23, 2007: Participants should travel to the Mount Shasta area and arrange accommodations in one of the motels in Weed or Mount Shasta City.

July 23, 2007: Participants will meet at 9:00 AM in room 8 of the Distance Learning Center on the College of the Siskiyous campus in Weed. Following introductions, the morning session will review the geologic setting of the southern Cascades. The class will break for lunch during the noon hour. The afternoon session, which will begin at 1:00 PM, will focus on the geologic processes that have shaped the landscapes of Crater Lake and Lassen Volcanic National Parks. It will include a lab period during which participants will have opportunities to examine hand samples of a variety of the rocks produced by the volcanoes. The afternoon session will end at 5:00 PM, with an opportunity for the group to get together informally over dinner at a local restaurant.

July 24, 2007: Participants will meet in the room LS-16 at 7:00AM to make sack lunches before boarding vans at 7:30 AM for a field trip to Crater Lake National Park. The group will explore sites that showcase the volcanic and glacial processes that shaped ancient Mount Mazama as well as those that accompanied the climactic eruption and caldera collapse. Background information and a road log for this trip will be provided. Participants who wish to take the boat tour of the lake should bring $20 to cover its cost, and should be prepared for the hike (900 vertical feet) down to the dock. Alternate field stops will be provided for those who do not take the boat tour. The field trip will end at the College at 7:00 PM, and participants will have the evening free.

July 25, 2007: Participants will meet in room LS-16 at 7:00 AM to make sack lunches before boarding vans at 7:30 AM for a field trip to Lassen Volcanic National Park. The group will visit sites that provide insights into key events in the history of the Lassen Volcanic Center and will include a 2-mile hike to Bumpass Hell, the most active thermal area in the park. Background information and a road log for this trip will be provided. The field trip will end at the College at 7:00 PM, and participants will have the evening free.

July 26, 2007: Participants will meet at 9:00 AM in room 8 of the Distance Learning Center. The morning session will review the geologic histories of Mount Mazama and the Lassen Volcanic Center, and include an overview of the ongoing seismic and geothermal activity at these sites. The class will break for lunch during the noon hour. The afternoon session, which will begin at 1:00 PM, will focus on the potential hazards posed by volcanism in the southern Cascades, and on strategies for integrating information on Cascade volcanism into a variety of courses. The class will conclude at about 4:00 PM.

Travel and Lodging

Traveling to Weed

Weed, California is located on Interstate 5 about 50 miles south of the California-Oregon border. For those traveling long distances it will probably be easiest to fly into one of the two regional airports (Redding, CA or Medford, OR), rent a car, and drive the last 75 to 85 miles to Weed. Medford is probably the best choice because there are now daily flights to both Denver and Salt Lake City. (All flights to Redding connect through San Francisco, which is subject to serious delays this time of year because of fog.) For those who have a few extra days to spend, an added advantage of having a car is that two other showcases of volcanic activity in the southern Cascades – Lassen Volcanic National Park and Crater Lake National Park – are each about a two-hour drive from Weed.

The Greyhound Bus Line also serves Weed, with a terminal located only about 3 blocks from the college campus. Finally, there is train service (the "Coast Starlight") to Dunsmuir, CA about 20 miles south of Weed. The northbound train usually stops in Dunsmuir between about 6 and 7 AM, and the southbound train usually stops around midnight. On weekdays public transportation is available from Weed to Dunsmuir via the "STAGE" (http://www.co.siskiyou.ca.us/dpw/transportation.htm). I will be available both before and after the course to help folks who might need a lift to make their connections.

Lodging in Weed

There are quite a number of motels, RV parks, and campgrounds in Weed and the surrounding area, and information on many of these is available from the business directory maintained by the Weed Chamber of Commerce (http://www.weedchamber.com/). Below is a list of motels and hotels within about a 10-minute drive of the campus along with their phone numbers that I hope you will find helpful for making reservations. If any of you are interested in sharing a room with another participant please let me know and I will try to match up interested parties.

Motel/Hotel: Address: Phone number:

Best Inn and Suites 1844 Shastina Dr. (5 min drive) (530) 938-1982

Hi-Lo Motel 88 South Weed Blvd. (10 min walk) (530) 938-2731

Holiday Inn Express 1830 Black Butte Dr. (5 min drive) (530) 938-1308

Motel 6 466 North Weed Blvd. (15 min walk) (530) 938-4101