cGPS Used to Study Slow Slip Landslide

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Project Overview

From February 12th through 16th, UNAVCO’s Dylan Schmeelk and John Galetzka joined UC Santa Cruz professor of Earth and Planetary Sciences Noah Finnegan (PI) and his graduate students Alex Nereson and Colleen Murphy in Oak Ridge in the mountains just east of Milpitas, CA to upgrade continuous GPS (cGPS) monitoring of the slow slip landslide at Oak Ridge Earthflow Observatory. The upgrade included two new cGPS sites (ORE2 and ORE3), a Vaisala weather station, communication systems to allow for remote data collection, and a power system upgrade to support the new equipment (at existing site OREO).

Significance

One of the key problems to understand in landslide mechanics and hazard prediction is why some landslides happen quickly, whereas other landslides slip slowly. The installation of cGPS at the Oak Ridge Earthflow Observatory is part of an ongoing project led by Noah Finnegan to study the complex interactions between groundwater flow and the deformation of the slow slip landslide located upstream of the Calaveras Reservoir.

Challenges

The slow moving landslide that OREO, ORE2 and ORE3 cGPS stations are monitoring is located nearest to the Calaveras Fault Zone, and mere miles from the intersection of the Mission and Arroyo Aguague faults, with the Hayward Fault Zone just to the west. Thus, the stations had to be engineered to withstand small, sudden movement of the landslide during seismic activity. Other engineering challenges included designing the cGPS stations to accomodate changes in groundwater pore pressure and to keep the bovine vandals from damaging the equipment.

Project Information

• Principal Investigator: Noah Finnegan
• UNAVCO Engineers: Dylan Schmeelk and John Galetzka
• Dates: February 12 – 16, 2018
• Location: Milpitas, California
• Funding Source: NSF-EAR
• Map of Calaveras Reservoir, California

Related Links

• NSF Award Abstract
• UCSC Geomorphology Research
• San Jose Faults