3 Tectonics and Magmatism in the Modern and Ancestral Cascades Volcanic Arc I

Wednesday, 2 April 2025
8:00 AM - 12:00 PM
Balboa/Calaveras

ACTIVE FAULTING OF LASSEN NP AND SURROUNDING AREAS

Paper number: 3-9
Program: Theme Sessions
Time: 10:25 AM – 10:45 AM

Authors

Abstract

Recent lidar surveys reveal numerous previously unrecognized active faults within Lassen Volcanic National Park (LVNP) and its surrounding area. This area connects predominantly strike-slip faulting in the northern Walker Lane with extension of the Hat Creek graben and other normal faults of the Modoc Plateau. Through the use of remote lidar interpretation and field mapping, we identified new strands of the Butt Creek Fault Zone and the Almanor Fault Zone. This mapping extends the Butt Creek Fault Zone further into the park to terminate near Lassen Peak. We observe evidence for normal and strike-slip along faults throughout LVNP, primarily concentrated in two zones of faulting with additional active faults between them. Individual faults strands range up to several kilometers in length, with scarps as high 35 m in Quaternary lava flows of the Lassen Volcanic Center. This work expands knowledge of the tectonic processes within Lassen Volcanic National Park and contributes to understanding of seismic hazards in northern California.

Geological Society of America Abstracts with Programs. Vol. 57, No. 4

doi: 10.1130/abs/2025CD-409835

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