Seismicity and fluid geochemistry at Lassen Volcanic National Park, California: Evidence for two circulation cells in the hydrothermal system

Response of hydrothermal system to stress transients at Lassen Volcanic Center, California, inferred from seismic interferometry with ambient noise

“…6b, the background LVC seismicity is concentrated at 3-6 km depth. A layer of thermal cracking with heatedhydrothermal fluid has been suggested to be responsible for clusters of the Lassen seismicity in this depth range (Janik and McLaren 2010), which in turn lead to a high-permeability zone and also reflect a volume of high porosity and high hydraulic diffusivity. In addition to the LVC seismicity, clusters of earthquake activity at volcanic areas are likely driven by hydrothermal fluid migration through highly permeable pathways (Waite 2002;Shelly et al 2013Shelly et al , 2015.…”

“…The majority of volcanic seismicity consists of clusters of earthquakes (or earthquake swarms) occurring over several days (Klein 1979). These seismic activities were likely linked to fluid pressure fluctuations from the Lassen hydrothermal system (Janik and McLaren 2010;Ingebritsen et al 2015).…”

Geologic field-trip guide to the Lassen segment of the Cascades Arc, northern California

“…Deep hot water also was encountered in a commercial geothermal well at Terminal Geyser, in an area subsequently incorporated into Lassen Volcanic National Park. This deep hot water may be from a separate geothermal upflow (Janik and McLaren, 2010) centered at either Devils Kitchen or Boiling Springs Lake in the southeast part of the park (figs. 11A and 12).…”

“…Diagrammatic cross sections of the Lassen hydrothermal system. The upper, northsouth cross section (A) illustrates circulation in cell 1 of Janik and McLaren (2010), whereas the lower, east-west cross section (B) illustrates circulation in their cell 2. In both cells, meteoric water percolates to depth and is heated by hot rock overlying a body or bodies of magma (shown generalized and diagrammatically).…”

Analyses of gas, steam and water samples collected in and around Lassen Volcanic National Park, California, 1975–2002

“…A recent publication by Janik and McLaren (2010) presents much of the gas chemistry and stable isotope data given here, but does not present location data for the samples. This report contains all available physical, chemical, and isotopic data for the samples presented in these earlier papers and includes other unpublished data.…”