Monday, November 11, 2013

The San Andreas fault at Cajon Pass

The San Andreas fault at Cajon Pass; this view is from one of our USGS-Caltech SoSAFz sites that I upgraded to improve low-latency GPS performance for use in the prototype earthquake early warning system. The red arrows point to the trace of the fault where it passes up Lone Pine Canyon towards Wrightwood, California in the distance. Los Angeles is behind (south, or to the left of) the San Gabriel Mountains in this photo. Click the small image below to see the full-res annotated photo.

What happens when...?

Sometimes a question is asked that you have never heard before; it challenges you to think differently about how to explain something to the public or to a student in clear terms, without jargon. I love it when that happens; a recent result is this interesting 'Critical Opalescence' Scientific American blog article by George Musser -- @gmusser --

Friday, January 25, 2013

San Andreas fault from Point Reyes to SFO, panorama from 10,500 meters showing the San Francisco Bay Area and other faults as well, such as the Hayward fault that runs through Berkeley. Photo taken on a flight from Beijing to Los Angeles on 20 January, 2013.

An article has been published on our new balloon LiDAR system - you can get the open access PDF file without a journal subscription (click for link).  [ ]

Monday, October 8, 2012

Hector Mine 1999 surface rupture

A group of us spent this past week (Oct. 1 - 5, 2012) back out at the Marine Corps Air Ground Combat Center (MCAGCC) in 29 Palms, CA re-investigating the 1999 surface faulting of the Hector Mine earthquake. We went into the Rainbow Canyon section of the base to work along the part of the fault that had the most slip. We're excited about what we discovered, including a location that seems to have had even more slip than had been measured by others back in 1999-2000. Recently, NCALM acquired new airborne LiDAR data that we'll use to compare with the original post-earthquake airborne LiDAR we obtained in April 2000. We are studying slip distribution, variation, and also fault scarp degradation processes. How landforms evolve along an active fault tells us about how long ago their last big earthquake was, and how active and hazardous a particular fault may be. Having a chance to study earthquake landform evolution in the earliest several years is especially instructive for us, and because this earthquake was on an "off limits" military base, it has actually been preserved especially well over the years. Participants this week included Prof. Joann Stock of Caltech and two graduate students, Frank Sousa & Janet Harvey, as well as Katherine Kendrick and Kate Scharer of USGS. We have taken all of the required safety training, obtained our badges for base access, and requested additional access from the MCAGCC over the upcoming months to continue these studies. This is an opportunity to use high-resolution, state-of-the-art airborne imagery to make special quantitative studies of extreme slip variation and 3D fault scarp degradation.

Thursday, May 24, 2012

B-LiDAR on the San Andreas - better than B4

Our team has just returned from successful and exciting field work, completing initial field tests of a prototype balloon-mounted LiDAR system along the San Andreas fault in the Carrizo Plain, with PI's Ben Brooks from Univ. of Hawai'i and Craig Glennie from the National Center for Airborne Laser Mapping (NCALM) at Univ. of Houston and the expert team including James Foster, Todd Ericksen and John Avery (Univ. of Hawai'i) and Darren Hauser (Univ. of Houston). Good news - the system works, the data are great! Watch Ben's 'Ignite UNAVCO' 5-minute talk, "The Balloon and the Lidar."

Thursday, April 26, 2012

Talk at annual meeting of the CRWUA

I was invited to speak at the annual meeting of the Colorado River Water Users Association (CRWUA) regarding the 2010 El Mayor - Cucapah earthquake and its impacts on water systems. Here is the meeting agenda web site, and here is the link to video of my presentation, entitled, "Impacts of the 2010 Mexicali Earthquake, Setting the Stage for Binational Collaboration." [intro starts at 29:45, and my talk begins at 31:00 in this video]