Sierra Nevada EarthScope Project (SNEP)

An NSF research highlight!

The REPORT OF THE ADVISORY COMMITTEE FOR GPRA PERFORMANCE ASSESSMENT FY 2007 highlighted SNEP as the significant earth science highlight in the NSF's goal of improving research infrastructure: "Imaging of a Foundering Lithosphere (0454524; 0454535; 0454554) Drs. Hersh Gilbert of Purdue University, Craig Jones of University of Colorado, Tom Owens of University of South Carolina, and George Zandt of University of Arizona analyzed NSF's EarthScope seismic data to identify a region where the mantle lithosphere is currently being stripped from beneath the Sierra Nevada batholith. As our understanding of processes related to the removal of mantle lithosphere improves, the important role played by lithospheric removal in continental deformation becomes increasingly apparent. Along the central portion of the western foothills of the Sierra, small earthquakes occur deep within the crust. These events may result from stresses associated with the lithospheric removal process. Resolution of EarthScope data has allowed a significant advance in understanding of the tectonics of mountain building and plate interactions. "

Who:

Name (alphabetical) email cell
Hersh Gilbert hersh@purdue.edu 520-237-6901
Craig Jones cjones@colorado.edu 303-995-3031
  Heidi Reeg heidireeg@gmail.com  
  Will Levandowski wlevando@gmail.com  
Tom Owens owens@seis.sc.edu 803-240-4007
  Ian Bastow ian.bastow @ bristol.ac.uk  
  Jordi Julià jordi@seis.sc.edu  
  Nickles Badger    
George Zandt zandt@geo.arizona.edu  
  Andy Frassetto andyf@iris.edu  

above is list of PIs/co-Is (in bold) and their postdocs and students. SNEP participants are also working with the Sierran Drips CD Project. We have also had help in the field and lab from IRIS interns Amanda Thomas and Scott Burdick (whose primary work was SNEP) and Christina Viviano and Monica Guerra (whose primary work was elsewhere) in 2005 and Will Levandowski (2006; he joined up with CU in 2008) , USC undergraduates Katrina Byerly, Nickles Badger, and Will Huff , CU graduate students Joya Tétreault, Gaspar Monsalve, Tom de la Torre, Chris Harig, USC staffers Charlie Groves, Philip Crotwell, U of A graduate students Andy Frassetto, Josh Calkins, Arda Ozacar , and CU volunteer Kristen Marano. Derry Webb from PIC helped in the field and many others at PASSCAL also have helped. (I think that is 26 people who have been in the field under the SNEP banner....)

SNEP mailserv is at South Carolina (along with list archives).

What, When, and Where:

~48 broadband seismometers were deployed from spring 2005 to September 2007 from about Kings Canyon National Park north to Honey Lake and west from the Central Valley into the Great Basin.

Analysis responsibilities are distributed with certain institutions taking the lead on different approaches:

Ambient noise tomography Univ. South Carolina
Body wave tomography Univ. Colorado, Boulder
Bulk crust from receiver functions Univ. South Carolina
Crustal receiver function anisotropy Univ. Arizona
Deep local earthquakes Purdue Univ.
Receiver function CCP imaging Purdue/Univ. Arizona
Regional waveforms Univ. South Carolina
SKS/S-wave splitting Univ. South Carolina
Sp receiver functions Univ. South Carolina
Teleseismic attenuation Univ. Colorado, Boulder
Teleseismic surface waves Purdue Univ.

Known problems, Phase I: (removal): 53, GPS removed by bear, 62 whole packer pulled by bear. (July service): 75 panel crushed; 65 GPS rare lock after 3/06, 14 GPS failed 1/2/06. (June '06 service): 64 was down much of winter, 55 sensor was way out of center, both noisy on horizontals??, 45, 46 and 56 down significant time (45 panel lost), 56 panel was partially loose, 86, 24 heavily damaged, 43 lost parameters and int batt dead, 23 battery dead (green box failure?), 63 junky sensor and flooded, 23 bad green box. (May '06 service) 52, 74, 22, 12, 84, 95, 67, 66, 57, 47, 36 all had problems at some level. flooded sites were 12, 52, 53, 95; others GPS and/or power problems. (over winter) 34 disk filled; (Jan) 42 stolen (replaced); 11 flooded (moved). 51,52,71 had leveling problems during high rain. Some east side GPS problems; (Oct '05) 74 opened by bear (lost power but recovered OK when reconnected); 21 has high frequency noise (no obvious solution), seems to have tilting problems (repeatedly loses horizontals), 22 had 6 second (?) timing error; repaired 8/3/05, 64 might need extra panel.

Phase II problems: Pullout, September 2007: 65-GPS died 07.056 (vault flooded and DAS died 07.133; sensor pins corroded) 87-GPS dead after 07.187 A8-Ch 3 dead 07.142, DAS stops dumping 07.178 B5-sensor or A/D noise after 07.176 C6-vault uncovered, noise on horizontals C8- GPS died after 24 hours and station down at 07.151 G5-Ch 1 dead after 07.246 May 2007: 12-powered down, short in sensor cable, 24-dead after one dump 55-plug pulled 87-GPS died 06.283 97-disk full 98-minor power outage towards end? A7-GPS out for 53 days B5-power system down after 07.068 B6-coherent noise on horizontals B7: power system failures after JD 94. E7-outages JD 30-60. January 2007: F9, very low sunlight, hole in DAS vault lid-now two panels and batteries, new lid; D4, D5, C4, E5, E4 frequent tilt-out of horizontals (autocentering frequency improved). GPS at E6 appeared to be misbehaving-replaced. Bear damaged B5 (repaired). C3 flooded; moved to shed above ground. 12 had no power--pin sleeve in solar panel cable was pushed back into connector. E7 was in the dark; panel moved 60' farther north. Disk problems from Jan. run disks from G9, E9. Power outages noted 96, E5, E4, E7, A4, F9 (more minor outages elsewhere). Stations we didn't try to visit (19): G7, F8, C8, C6, B6, A5, 87, 86, 85, 75, 65, 64, 55, 34, 24, 14, 84, 74, and 63. So 33 of our 52 stations were visited.

Other maps

Map of SPE and SNEP2005 deployments on geologic base, with ES stations as of April 2006 (click for pdf version):

Geologic Map with SPE, SNEP 2005 stations

Map of all Sierran portable passive deployments, 1988-2007, and US Array stations: (click for larger version) (need to adjust for final SNEP deployment)

Full Sierra Station Map

Why:

To better understand the physics of removal of mantle lithosphere and the consequences of such tectonism.

Meetings:

Proposal documents:

The 2004 Earthscope proposal

Animation of Sierran uplift histories (a figure from Jones et al)--shockwave.

Fieldwork:

Field materials now on an archive page

Photo websites:

Cartoon of installation

 

Calendar: (Older calendar for reference)

Date Event
December 2007 AGU meeting, San Francisco
November 2-4, 2008 workshop with Sierran Drips CD project members, Tucson
Fall, 2009 workshop with Sierran Drips CD Project, Boulder, Colorado
December 2010 Deadline for papers to special issue of Geosphere.

Resources:

Maps:

GMT files: (and a simple script to build a station map)

Publications:

In process:

S-wave paper, local earthquake paper (both hopefully showing up in 2019).

Theses:

Abstracts:

AGU, San Francisco, Dec. 15-19 2008--see list of presentations of potential interest to SNEP

GSA, Houston, October 2008

IGC, Oslo, August, 2008

AGU, San Francisco, Dec. 2007

AGU, Acapulco, 22-25 May 2007

AGU, 11-15 December 2006

IRIS Meeting, June 8-10, 2006, Tucson, AZ

AGU, 5-9 December 2005

GSA, October 2005

IRIS Meeting, 19-21 June 2003, Fish Camp, CA: (click for abstract)

Reprints/Preprints of interest:

 

Some other info on Sierran Paradox experiment webpage

This material is based upon work supported by the National Science Foundation under Grants Nos. 0454535, 0454524, and 0454554 to CU, USC, and U of A, respectively. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


Please send mail to cjones@colorado.edu if you encounter any problems or have suggestions.

C. H. Jones | CIRES | Dept. of Geological Sciences | Univ. of Colorado at Boulder