Saturday, November 15, 2014

SoSAFE and Earthquake Geology Geochronology workshop report (Southern California Earthquake Center)

Kate Scharer (USGS), Mike Oskin (UC Davis) and I organized a geochronology workshop for the Southern California Earthquake Center community this fall. We emphasized methodologies useful for investigating fault slip behavior over time scales from 102 to 106 years. That included Terrestrial Cosmogenic Nuclides, Uranium Series, and Optically Stimulated Luminescence. We did not talk so much about 14C given its relative maturity, but we certainly recognize its continued value.

Kate lead the charge on the completion of the workshop report. It has a nice summary of the topics covered (here is the original agenda). I had a sense of a real acceleration in the number and quality of applications of the methods and the resulting rich depiction of deformation rates and their variations across time and space in Southern California. I was particularly moved by the climate modulation on the development of landforms (alluvial fans, channels, etc.) that serve as markers as well as the possible temporal coherence of wet and dry times across the region. I think that this modulation and coherence can be exploited with more intensive application of geochronology.

I learned a lot more geochronology, especially having just been at the EarthScope Geochronology Institute a week or so earlier--note that the talks and some of the videos are up (where we covered some similar topics and where Kate was a speaker on 14C). It was very nice to see many SCEC friends and colleagues.

Tuesday, November 11, 2014

Fall 2014 Workshop on the Future of the Amphibious Array

Led by Professor Geoff Abers (speaking above), we organized the Workshop on the Future of the Amphibious Array which was held at Snowbird in the Wasatch Mountains of Utah--and which I remember well from early EarthScope meetings.

The workshop charge was to make the case for further amphibious experiments (emphasizing the idea of crossing the shoreline). We need to articulate the case for integrated amphibious science. And, we were to evaluate the Cascadia experience. We were guided by the EarthScope Science Plan and by the GeoPrisms planning documents. I also helped summarize a breakout session. Here is the PPT.

Greg Anderson from NSF was traveling with Silverwing:

I had a decent view of the Grand Canyon on the way home:

GSA Annual Meeting 2014

I spent almost a week in Vancouver, CA for the Geological Society of America Annual meeting. It is a very beautiful city with dramatic views and great food.

--view from the convention center

Becky Flowers giving science motivation talk at the EarthScope Geochronology and the Earth Sciences Institute and short course. The short course was my main purpose for being there as I helped to organize it. I learned a lot. For example, a date is an outcome of the analysis and calculation, while age is an interpretation (S. Bowring). I gave a welcome (PPT) and an EarthScope science motivation talk (PPT).We kicked off the Gecchronology student award program: PPT. We have a number of videos of the presentations and the pdfs, etc. which should be on line soon.

I also enjoyed seeing many old friends and colleagues.

Fall 2014: PATA-Days in Busan, Korea

I had a wonderful trip to Busan, Korea for the Paleoseismology, Active Tectonics, and Archeoseismology (PATA Days) meeting. I really enjoyed it. It was great to see old and new friends, catch up on the latest developments, and to travel in southern South Korea.
Here is a presentation/overview I made for my students and colleagues for our seminar:
Here is the paper I wrote for the meeting: pdf.

I spent some nice time with my friends Koji Okumura and Shmulik Marco:

It was also an interesting trip because my father was based at the Pusan East (K-9) air base in 1951. He was curious to hear about the trip and mentioned that he turned 21 there. He said they played a lot of cards and that a few times he got to go off base to help his friends who worked at a reservoir.

Monday, September 29, 2014

Some TU Dresden SfM and lidar links

I got a nice tip from Univ.-Prof. Dr. Klaus Reicherter about some good structure from motion (SfM) and lidar links at the Technical University Dresden:

I also note for reference that we have the OpenTopography Tool Registry

Friday, September 12, 2014

Southern California Earthquake Center 2014 meeting group picture

Many of my students and colleagues and I just returned from the 2014 Southern California Earthquake Center meeting. It was really great: so much energy, so many old and new friends and colleagues. It is a very strong community with a world-leading emphasis on earthquake system science. I am on the Planning Committee and was very engaged many aspects of the meeting.

Here is a fun picture from the meeting:

Back row: Kate Potter (ASU), Kendra Johnson (Colorado School of Mines), Ed Nissen ((Colorado School of Mines), Wei Zhanyu (Chinese Earthquake Administration). Front row: Emily Kleber (ASU), Barrett Salisbury (ASU), me, and Gayatri Marliyani (ASU). I am always proud of my students and associates!

I flew to Palm Springs for the meeting and on the flight home, I had a nice view of the San Andreas Fault zone in the Indio Hills just to the east of Palm Springs and the meeting location. Here are two pictures:

The main fault trace cuts diagonally across the middle of the upper view. Two large scale right lateral offsets are evident along the fault. On the right side of the lower image, secondary (normal?) faults cut the uplifted alluvial fan units.

Along the San Andreas Fault in this area the the B4 laser scan data were collected by the Ohio State University, the National Center for Airborne Laser Mapping, USGS, and UNAVCO. The data are available on line at OpenTopography. Here is a screen capture of the hillshade in google earth:

And, here is the kmz file for that area of the hillshade of the DEM I calculated at OpenTopo.

Sunday, August 24, 2014

24 August 2014 M6 Earthquake northern San Francisco Bay area (6km NW of American Canyon, California)

An M6 strike-slip earthquake occurred in the northern San Francisco Bay area last night (3:20 am local time). It is reported as 6 km NW of American Canyon and between Napa and Vallejo. This is the biggest event in the Bay Area since the 1989 M6.9 Loma Prieta earthquake. Aftershocks are following and will continue. Not a lot of additional data and interpretation are yet available, but they will be soon! There might be some surface rupture, and there should be coherent ground cracking (could end up being a semantic point!). There will be a lot of landslides, and there seems to be structure damage in especially some of the older brick buildings in the region. It sounds like people have been injured from falling debris. I hope everyone will be ok. The Did You Feel It mapping shows that shaking was very strong to severe in the north Bay area and it was felt widely across the region.

The UC Berkeley Seismological Laboratory and the Southern California Earthquake Center Data Center (link) have nice maps and lists showing the location of the main shock and the aftershocks elongate along the rupture zone. There is some useful commentary about the faults and their recent activity at the bottom of the main Main USGS page on the event.

The earthquake occurred in the area of the West Napa Fault. The focal mechanism is consistent with the expected right lateral slip. I made the figure using the USGS Quaternary Faults data base and the focal mechanism from the USGS. The center of the focal mechanism is on the epicenter.

Here is a kmz of the hillshaded digital elevation model (Napa watershed gathered by National Center for Airborne Laser Mapping in 2003) at 2 m resolution of the area of the main shock (click to download the kmz):

I georeferenced one of the maps from the Wesling and Hanson final technical report (click to download the kmz). Lineaments are targets for field survey:

Here is folder with georeferenced images.

I notice a Plate Boundary Observatory station not far from the southern end of the likely rupture zone (P261), but no updates yet for today to see a change in its position. There are also borehole strainmeters that apparently felt the squeeze.

Here are a few links: