Presentation Title

Geophysical Imaging of Shallow Conduits for Carbon Dioxide Emission at Horseshoe Lake, Mammoth Mountain, California

Faculty Mentor

Jascha Polet

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 144

Session

Poster 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Geophysical Imaging of Shallow Conduits for Carbon Dioxide Emission at Horseshoe Lake, Mammoth Mountain, California

Ashley Rivera and Jascha Polet

Emission rates of carbon dioxide in Horseshoe Lake (HSL) increased to dangerous levels following a swarm of earthquakes recorded beneath Mammoth Mountain volcano between 1989 and 1990. Previous research suggests that a magmatic intrusion that coincided with this earthquake swarm allowed CO2 exolving from cooling magma to penetrate the shallow subsurface through conduits with superior permeability. Denser CO2 settles close to the surface and prevents the absorption of oxygen needed for photosynthesis, resulting in tree-kill areas in HSL. A study conducted between 1997 and 2000 determined that CO2 efflux at HSL falls in a range of 49–133 t day-1, but later studies indicate that the efflux has slowly decreased with time. We seek to image possible faults or fractures in the shallow subsurface which could act as a conduit for these CO2 emissions. In July of 2017 a geophysics field class used ground penetrating radar (GPR), an electro-magnetic profiler, and a magnetometer to evaluate the geophysical properties of the subsurface where studies suggest the CO2 efflux is highest. The data collected was used to generate profiles of any discontinuities in the subsurface, maps of shallow conductivity, and the intensity of the overall Earth’s magnetic field. The GPR profiles indicate several areas where subsurface interfaces appear to be disturbed. Preliminary results for measurements of the total magnetic field intensity appear to show anomalies consistent with known areas of high CO2 emissions; however there is no such correlation for the electro- magnetic profiler data.

Keywords: Horseshoe Lake, Carbon Dioxide, Conduits, Geophysics, Volcanism, Imaging, Faults

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Geophysical Imaging of Shallow Conduits for Carbon Dioxide Emission at Horseshoe Lake, Mammoth Mountain, California

BSC-Ursa Minor 144

Geophysical Imaging of Shallow Conduits for Carbon Dioxide Emission at Horseshoe Lake, Mammoth Mountain, California

Ashley Rivera and Jascha Polet

Emission rates of carbon dioxide in Horseshoe Lake (HSL) increased to dangerous levels following a swarm of earthquakes recorded beneath Mammoth Mountain volcano between 1989 and 1990. Previous research suggests that a magmatic intrusion that coincided with this earthquake swarm allowed CO2 exolving from cooling magma to penetrate the shallow subsurface through conduits with superior permeability. Denser CO2 settles close to the surface and prevents the absorption of oxygen needed for photosynthesis, resulting in tree-kill areas in HSL. A study conducted between 1997 and 2000 determined that CO2 efflux at HSL falls in a range of 49–133 t day-1, but later studies indicate that the efflux has slowly decreased with time. We seek to image possible faults or fractures in the shallow subsurface which could act as a conduit for these CO2 emissions. In July of 2017 a geophysics field class used ground penetrating radar (GPR), an electro-magnetic profiler, and a magnetometer to evaluate the geophysical properties of the subsurface where studies suggest the CO2 efflux is highest. The data collected was used to generate profiles of any discontinuities in the subsurface, maps of shallow conductivity, and the intensity of the overall Earth’s magnetic field. The GPR profiles indicate several areas where subsurface interfaces appear to be disturbed. Preliminary results for measurements of the total magnetic field intensity appear to show anomalies consistent with known areas of high CO2 emissions; however there is no such correlation for the electro- magnetic profiler data.

Keywords: Horseshoe Lake, Carbon Dioxide, Conduits, Geophysics, Volcanism, Imaging, Faults