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

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):

Monday, September 2, 2013

Short Course at LIPI : Techniques in Active Tectonic Study

In July 2013, Gayatri Marliyani and I taught a short course at LIPI in Bandung, Indonesia on Techniques in Active Tectonic study. I put together almost 30 lectures on various topics in active tectonics, neotectonics, tectonic geomorphology, paleoseismology, earthquake geology, and related topics. Special thanks to Mudrik Daryono (course coordinator for LIPI/ITB/GREAT), Irwan Meilano (ITB/GREAT), Danny Hilman Natawidjaja (LIPI/GREAT), Eko Yulianto (LIPI/GREAT), and the participants.

Gayatri built a nice website with all of the freely available lectures and other course content. We also recorded most of the lectures and they are on youtube.

The course web site is: Look under the schedule link for the lectures and the link for some exercise content.

Group picture on field trip along the Lembang Fault.

Exploring topographic response to interacting surface processes and rock uplift: the Dragon's Back Pressure Ridge along the San Andreas Fault, Carrizo Plain, CA

The Dragon's Back Pressure Ridge is an amazing landform along the San Andreas Fault in the Carrizo Plain of California. A recent paper in Science by Hurst, et al. examined it to explore how hillslope form might be used to indicate waxing and waning responses to a pulse of rock uplift. George Hilley (a coauthor on the recent paper) and I along with David Pollard and Dallas D. Rhodes have spent more than 20 years pondering and exploring the Dragon's Back. With this blog entry I want to highlight a few links for more information.

This is the main published paper on the Dragon's Back up to now: Hilley, G. E., and Arrowsmith J R., Geomorphic response to uplift along the Dragon's Back pressure ridge, Carrizo Plain, California, Geology, v. 36; no. 5; p. 367–370; doi: 10.1130/G24517A.1, 2008.

Ph.D. theses:

  • Arrowsmith, JR, 1995, Coupled Tectonic Deformation and Geomorphic Degrada tion along the San Andreas Fault Zone [Dissertation thesis]: Stanford, Stanford University.
  • Hilley, G. E., 2001, Landscape development of tectonically active areas [Dissertation thesis]: Arizona State University.

Hillshades and digital elevation model (B4 project data processed by OpenTopography):

Other links:

The digital elevation models that enabled much of the analysis discussed here come from the B4 project and the data and models are available from OpenTopography.
The B4 project created an unprecedentedly accurate surface model along the San Andreas and San Jacinto Faults in southern California that enabled the research reported here. It was supported by the U. S. National Science Foundation and led by Ohio State University and the U. S. Geological Survey. The National Center for Airborne Laser Mapping performed the airborne data acquisition and laser data processing. Optech International generously contributed use of the ALTM3100 laser scanner system. UNAVCO and SCIGN assisted in GPS ground control and continuous high rate GPS data acquisition. A group of volunteers from USGS, UCSD, UCLA, Caltech and private industry, as well as gracious landowners along the fault zones, also made the project possible.

Tuesday, July 9, 2013

Field blog: Welcome to a field season at Ledi-Geraru, Afar, Ethiopia! by Erin DiMaggio

Erin DiMaggio was invited to write a field blog for the GeoPrisms Spring 2013 newsletter. She presents a nice set of highlights from our recent field season at Ledi-Geraru, Afar, Ethiopia. The link is here:

Monday, March 18, 2013

LaDiCaOZ and Lateback: reconstructing horizontal offsets in topography websites for tools

Dr. Olaf Zielke developed some very useful tools for interacting with high resolution topography for horizontal back slip of offsets due to earthquakes. These were the tools for the science results presented in:

  • Zielke, O., Arrowsmith, J R., Grant Ludwig, L., Akciz, S. O., High resolution topography-derived offsets along the 1857 Fort Tejon earthquake rupture trace, San Andreas Fault, Bulletin of the Seismological Society of America, doi: 10.17850120110230, vol. 102 no. 3 1135-1154, 2012.
  • Zielke, O., Arrowsmith, J R., Grant Ludwig, L., Akciz, S. O., Slip in the 1857 and earlier large earthquakes along the Carrizo Plain, San Andreas Fault, Science, DOI: 10.1126/science.1182781, p. 1119–1122, 2010.
He also documented the approach and the software in this paper:
Zielke, O., and J R. Arrowsmith, LaDiCaoz and LiDARimager -MATLAB GUIs for LiDAR data handling and lateral displacement measurement, GeoSphere Special issue on high resolution topography, v. 8, no. 1, p. 206221, doi:10.1130GES00686.1, 2012.

Olaf is now at KAUST. His email address is:

He has made the supplemental on line material from the Geosphere paper available here.
And, the LaDiCaoz_LiDARimager tools and information is available on this dropbox link

This research was supported by the US National Science Foundation, the US Geological Survey, and the Southern California Earthquake Center.

Tuesday, February 12, 2013

Collecting some links on the North Korean nuclear test

Valuable information about North Korea's nuclear test comes from seismological recordings of the shock waves produced in the event.

One of the interesting things is that because the North Korean nuclear tests are basically done in the same place, seismograms of the events at long distances have quite similar characteristics. Their amplitudes, however, do vary with the increasing yield of the events.

Here are a few links I have come across:

How do we know it was an explosion and not an earthquake? First of all, that part of North Korea is not known for historic earthquakes. Secondly and more to the point, with seismometers arrayed around the source area regionally and globally, the explosion will cause all of the first motions to be AWAY from the source. If it is an earthquake, two quadrants will be pulled IN towards the source and two quadrants will be pulled out ("double couple").

--disclaimer: this is not my area of expertise, but I do find it fascinating. To some degree, monitoring of nuclear tests using seismology has driven the development of seismology and seismic networks and that lets us learn a lot more about earthquakes globally.

Thursday, February 7, 2013

Paleoanthropology research in the Afar, Ethiopia

I just got back from some fun field work in the Afar, Ethiopia. Here are some pictures. Our project there is called the Ledi-Geraru Research project. The research is done in collaboration with Kaye Reed and Chris Campisano from the Institute of Human Origins / School of Human Evolution and Social Change as well as with Ph.D. students Erin DiMaggio and Dominique Garello. Erin is just finishing up a substantial Ph.D. effort on the geology, stratigraphy, and tephrachronology of rare Pliocene units (about 2.9-2.7 Ma) that critically span a time gap otherwise mostly missing in the region. Dominique will be working with Chris Campisano and I on the geology of the Ledi-Geraru, as well as this drilling project.

Here are a few other posts on this topic:
We started this project with Charlie Lockwood and miss the chance to share its successes with him.
Here is an old page with maps
Here are many pictures from over the years:
Ethiopia and Afar region (2002)
Ethiopia and Afar region (2004)
Ethiopia and Afar region (2005)
Ethiopia and Afar region (2006)
Ethiopia and Afar region (May 2008)
Web-sized images for Ethiopia and Afar region (November 2008); Ethiopia and Afar region (November 2008) full size images
Web-sized images for Hadar Field School (2009); Hadar Field School full size images
Afar region 2012
Afar region 2013