Jun 1, 2016
Historic drought puts the brakes on earthflows in Northern California
Geophysical Research Letters
- Assesses the California drought's impact on 98 deep-seated, slow-moving landslides in Northern California
- Uses aerial photograph analysis, satellite interferometry, and satellite pixel tracking to measure earthflow velocities spanning 1944–2015 and compares these trends with the Palmer Drought Severity Index, a proxy for soil moisture and pore pressure that governs landslide motion
- Finds that earthflow velocities reached a historical low in the 2012–2015 drought, but that their deceleration began at the turn of the century in response to a longer-term moisture deficit.
- Analysis implies depth-dependent sensitivity of earthflows to climate forcing, with thicker earthflows reflecting longer-term climate trends and thinner earthflows exhibiting less systematic velocity variations
- Findings have implications for mechanical-hydrologic interactions that link landslide movement with climate change as well as sediment delivery in the region