Tuesday, April 1, 2014

Links and comments on M8.2 - 95km NW of Iquique, Chile April 2, 2014

This evening there was a M8.2 earthquake along the northern Chilean subduction zone. It caused very strong shaking along the Chilean coast. There have been numerous aftershocks. It was appropriately configured to generate a tsunami. Max heights in the source region are 2 m. It appears that beyond Chile and Peru the tsunami concerns are low (I saw that the expectation was ~20 cm in coastal California).

The Chilean portion of the subduction zone along western South America has generated the largest recorded earthquake historically (in 1960 M9.5; That was on the southern end of the zone). This is in an area where there has been some strong locking noted.

Here are some links:

  • USGS main page: Summary Includes estimated losses (pager) and also expected (shakemap) and felt (dyfi) intensities.
  • Here is low dip focal mechanism consistent with expectations: scientific

Here is the IRIS Teachable moment page. I has some nice content for presentations on the event.

This map may work to show the local seismicity: http://earthquake.usgs.gov/earthquakes/map/ Navigate to the region and zoom in.
Try this one too: http://www.iris.edu/seismon/ see this: Regional focus

Pacific Tsunami warning center: Pacific region see the Pacific region statement: text Here is the forecast tsunami height map and the travel time map

This site is accumulating observations: http://earthquake-report.com/2014/04/01/massive-earthquake-offshore-tarapaca-chile-on-april-1-2014/

Image showing degree of seismic coupling and location: http://t.co/rgwmyacIw1. See this paper: http://gji.oxfordjournals.org/content/194/3/1283.full

Good blog entries:
Quakehunters

Here are a few useful news links:
http://www.latimes.com/world/worldnow/la-fg-wn-chile-quake-larger-20140401,0,2045484.story#axzz2xgQBG1Wx
http://santiagotimes.cl/8-2-quake-hits-northern-chile-triggering-regional-pacific-wide-tsunami-warning/

Some more educational links:
Tsunamis Generated by Megathrust Earthquakes from IRIS

Monday, March 31, 2014

Exploiting high resolution topography data for advancing the understanding of mass and energy transfer across landscapes: Opportunities, challenges, and needs (USGS Powell Center working group)

"TIME FOR IN-DEPTH ANALYSIS WITHOUT DISTRACTIONS"--That is one of the opportunities presented to USGS Powell Center Working Groups. Indeed and quite pleasantly we have begun our discussions in the working group entitled "Exploiting high resolution topography data for advancing the understanding of mass and energy transfer across landscapes: Opportunities, challenges, and needs". This project is lead by Paola Passalaqua (UT Austin) and Patrick Belmont (Utah State). Here is a flyer on our project: link. We had our first meeting a couple of weeks ago in Fort Collins at the Powell Center and it was extremely stimulating. Lots of great discussion and sharing of ideas among a dynamic group. I very much enjoyed seeing old and new friends. We mostly worked on brainstorming a big review of the state of analysis of high resolution topography and so I think there will be a publication coming from that. We also had a quite interesting field trip to appreciate the geomorphic responses to the High Park Fire (for which there is some repeat lidar topography coverage). Here are some pictures. Stay tuned for more cool stuff and many thanks to my friends and colleagues for the chance to work together.

Friday, February 28, 2014

Science videos: naive efforts and connecting with the pros (for example, http://lifeonterra.com/)

I have been playing around with video production for science explanation and tutorials since some efforts in graduate school for the The Stanford Rock Fracture Project. Lately, I have generated many tutorial and lecture videos and pushed then to my youtube site: jrarrowsmith youtube. There are also many videos, some have been viewed more than 10,000 times on the OpenTopography youtube site.

My friend Merri Lisa Trigilio is a geoscientist who is now in the Film program at Montana State University. It has been fun to talk to her about filmmaking and we will work together in the coming weeks on a video project. Stay tuned for updates. I the meantime, have a look at the Life on Terra website--run by the film students at MSU.

As part of a Southern California Earthquake Center (SCEC) and OpenTopography collaboration, Sarah Robinson (former ASU M.S. student) and Andrew Whitesides (USC undergraduate) - supported by SCEC's ACCESS program (Advancement of Cyberinfrastructure Careers through Earthquake System Science) and in collaboration with numerous SCEC scientists and the OpenTopography team - produced a new educational video entitled LiDAR - Illuminating Earthquake Hazards. The video provides an introduction to both LiDAR technology as well as the earthquake science that is being done with the data.

Thursday, January 23, 2014

Spring 2014 Active Faulting and Surface Process Seminars

We have two nice seminars going now: Active Faulting and Surface Processes.

We have started to run the Active Faulting seminar and track it the last few semesters. Thanks to Emily Kleber and the other students for taking the lead and organizing and documenting. Emily says: "This semester we are focused on discussing current research projects and trending topics in active tectonics and tectonic geomorphology. Subject matter is centered around (but not limited to) quantitative structural geology, geomorphology, paleoseismology, and the acquisition and application of high-resolution topography to all of the above." Here is the web site: http://activetectonics.asu.edu/ActiveFaultingSpring2014.html .

The Surface Process seminar has been going since at least Spring 2008. The topics vary and it is run in the evenings at a faculty member or student home. We enter the critical zone of commentary and sometimes the topic is about the Critical Zone (from the top of the canopy to the bottom of the roots). This semester's topic is generally hillslope processes.

Saturday, December 14, 2013

Exploring the Topographic Evolution of Cinder Cones

At the Fall AGU 2013, I presented a summary of work done by Emma Gleeman (Brown) and Sarah Zibart (Western Kentucky University) along with Amanda Clarke (ASU) and Fabrizio Alfano (ASU) as part of the Research Experience for Undergraduates: Landscape evolution in a monogenetic volcanic field led by Nancy Riggs at NAU and supported by the US National Science Foundation. Among other things, we used the 2D non linear diffusion code developed by Mattia de’ Michieli Vitturi (de’ Michieli Vitturi and Arrowsmith, Two-dimensional nonlinear diffusive numerical simulation of geomorphic modifications to cinder cones, Earth Surf. Process. Landforms (2013) and built on our good collaborations with Mattia.

Here is the presentation: pptx and pdf


Picture from the Autokite

Conclusions include:

  • Agglutinate is important in controlling cinder cone topographic development
    • Not extremely important for h/w ratios (age approximation)
    • Significant in controlling slope histogram
  • High resolution topography is required for good characterization of slope distributions, esp. for cones with agglutinated tops
  • 2D non-transport-limited linear diffusion and 1D production-limited linear diffusion models reasonably captured evolution of both agglutinated and non-agglutinated cones
  • Laboratory experiments agreed with histogram evolution predicted by numerical modeling for both agglutinated and non-agglutinated cones
  • Additional process rules (short range sheetwash, fluvial, and debris flow) of scoria and aeolian material is a next step

Monday, November 11, 2013

Imaging and Analyzing Southern California’s Active Faults with Lidar: A joint SCEC, OpenTopography, UNAVCO and EarthScope short course

We ran a short course last week at San Diego Supercomputer Center:
Imaging and Analyzing Southern California’s Active Faults with Lidar
It was a joint Southern California Earthquake Center, OpenTopography, UNAVCO, and EarthScope workshop. It was intense and fun and I certainly enjoyed getting to know everyone. Thanks go to Chris Crosby and Emily Kleber for all of the organizing and to Edwin Nissen and Peter Gold for their contributions in the lectures.

We got to see one of my favorite sculptures: the Cat in the Hat with Theodore Geisel UC SD library link. Here I am next to them:

Workshop on high resolution topography applied to earthquake studies (Earthquake Research Institute, Tokyo, Sept. 18-20, 2013)

We held a workshop on high resolution topography applied to earthquake studies as part of the Virtual Institute for the Study of Earthquake Systems (VISES) activity lead by the Southern California Earthquake Center at the Earthquake Research Institute in Tokyo, Sept. 18-20, 2013.

The planners of the workshop were me and Koji Okumura from Hiroshima University along with Chris Crosby (UNAVCO), Mike Oskin (UC Davis), Edwin Nissen (Colorado School of Mines), and Shinji Toda (Tohoku University).

I just completed the workshop report pdf link.

We came up with a few recommendations that are worth pulling out of the report:

  1. There has been an interesting evolution of methodology for study of active faulting and topography. LiDAR has revolutionized many tasks and our ability to measure surface features at the fine scale at which the surface processes and earthquake deformation operate.
  2. The challenge of identifying active faults in topography (especially in areas of low fault slip rates and high surface process rates and heavy vegetation) remains. A standardized approach of morphology delineation followed by detailed surficial geologic mapping should yield defendable fault traces and indication of potential detailed study sites.
  3. Once faults are identified, reconstructing offset and deformed features is necessary. A combination of field and virtual approaches was advocated. Uncertainty assessment in the reconstructions is an active area.
  4. A substantial emphasis has been on surface rupture characterization in high resolution topography acquired shortly after an earthquake. This effort includes airborne and terrestrial laser scanning data integration. Examination of tilted trees in the vegetation (Yoshimi) was a clever use of the three dimensional data to characterize surface deformation along the earthquake rupture.
  5. High relief areas such as parts of Japan and southern California are susceptible to landslides and their interaction with active faults is notable. In addition, their methods of study using high resolution topography are similar.
  6. Topographic differencing along Japanese and the El Mayor Cucupah earthquake ruptures is yielding exciting results that seem to document variable continuity of slip along fault surfaces in the upper several hundred meters below the Earth surface. These results are complementary with the wide aperture INSAR results typically coming from earthquake studies. The various approaches for differencing (Iterative closest point, image correlation, pixel matching, particle image velocimetry, etc.) should be systematically compared.
  7. Ongoing training and knowledge exchange of the sort done here is valuable.
  8. It is important to facilitate community access to high-resolution, Earth science-oriented, topography data, and related tools and resources. This is the mission of OpenTopography. We discussed these ideas and that open access was desirable, but topographic data in particular in Japan tends to be difficult to obtain for scientists without purchasing it (despite the data having been paid for initially by public funds).

Here are a few pictures from the trip (note that all were taken by Koji Okumura):