105 year anniversary
Active Norcal interviewed Forrest Hopson, author of Geology of the Lassen Country, about the May 22, 1915 eruption of Lassen Peak in honor of the 105th anniversary of that eruption.
Eruption of Lassen Peak
Lassen Country Hikes
Updated Hiking Maps
The book’s trail guide showcases the geologic history of the Lassen country. We have selected hikes that provide examples of the Lassen Volcanic Center and regional geology. USGS 1:24,000 scale maps show the trails and parking locations. The guide is illustrated but watch for references to figures and tables in previous chapters. Also, important background information about the geology in each hiking guide is discussed.
Continue ReadingBumpass Hell Trail
Geology of the Lassen Country
The Bumpass Hell Trail is one of the most popular destinations in the Lassen Country. The trailhead is at the large parking area 0.25 mile (0.4 km) east of Lake Helen. The trail traverses the dacite of Bumpass Mountain for the majority of the hike. Also, note the well-preserved glacial polish and striae in the dacite alongside the first few hundred yards of the trail. They were created by the glacier that started from the Lake Helen cirque. At the viewpoint where the trail turns east, about 0.5 mile (0.8 km) from the trailhead, it crosses briefly into andesite of Mount Diller. Here a National Park Service trailside interpretive display shows a model of Brokeoff Volcano before erosion.
Trailhead: Bumpass Hell trailhead parking lot
Distance: 3.0 miles (4.8 km) round trip
Key Geologic Features: Hot springs, clay-altered bedrock
Lassen Geology
The Earth is not always quiet. An isolated region of northeast California offers a land of boiling springs, steaming sulfur vents, mud pots, and volcanoes. The boisterous geology of the southern Cascades is defined by Lassen Volcanic National Park. A complex and compelling geologic story is told in The Geology of the Lassen Country, a new book by R. Forrest Hopson and Michael A. Clynne.
