There is some LOS displacement across the SH fault in the 2010/03/09-2010/04/13 Envisat interferogram for Track 306, although it's a bit swamped by the correlated atmospheric noise.

You have probably heard that the El Mayor Cucapah earthquake caused extensive liquefaction in the agricultural area of Baja California (far greater than the U.S. experienced).   What may be news to you, as it was to a few of us from Exponent as we were shown around the area, is just how serious the effects of liquefaction are to Baja.

 There are photos attached to see for yourself, but the big issues related to the liquefaction are:

 DAMAGED IRRIGATION CANALS.  Liquefaction and lateral spreading caused cracking, settlement, and slumping of concrete-lined irrigation canals.  The Baja government estimates that 300 km of canals are damaged.  Repair of the canals will take much time and money.

 CROP DEATH.  Most crops currently in the fields are likely to be lost this season due to lack of ability to water them.  This means shortages of the products (largely wheat and alfalfa).

 FLOODING.  Portions of the agricultural areas were inundated with water from sand boils and other sources.  Standing water remains in some roadside ditches and fields, killing the plants.

 FIELDS NO LONGER LEVEL.  Massive sand boils and other deposits blanket parts of fields, and large-scale lateral spreading created scarps and fissures that cross fields.  The resulting uneven topography will require earthwork and leveling before gravity-controlled irrigation can resume.

 HUGE AREA TO REPAIR.  The Baja government estimates that 140,000 acres need to be repaired.  Many hours per acre are required to perform the earthwork, and laser-leveling equipment is in too-short supply.  The extent of acreage damaged overwhelms repair capabilities. 

 ECONOMY HIT.  With this year’s crops lost, local economies are seriously impacted.  Farm workers are out of work, as are suppliers and distributors.   300,000 families are thought to be largely out of business due to the earthquake.  Lack of money in the small communities also affects cities like Mexicali.  Farm workers and other impacted residents may look for work in the U.S.

 SAME THING NEXT YEAR.  If repairs to irrigation canals and fields cannot be completed this summer, next year’s crops will not be planted.

 FUNDING.  The Baja government and the citizens need financial help repairing the damage.

 Please keep the Baja issues in mind when talking to others.  It is a shame that such a severe situation is not known by most people outside of Mexico.

 Heidi Stenner & Betsy Mathieson

hstenner@exponent.com

Widespread landslides are presumably responsible for massive dust clouds seen over the Cucapah mountains immediately after the earthquake,

http://www.ireport.com/docs/DOC-428979?ref=email

and likely contributed to decorrelation of radar images in that area,

http://igpp.ucsd.edu/~fialko/baja.html

John Fletcher and his students, along with Tom Rockwell and Karl Mueller, have spent the most time mapping in the field and traversing the canyons that are reportedly full of rockfalls. I did not take any photos of rockfalls while in the field. You may also look through the photographs that Ken Hudnut took from the helicopter survey of the fault on April 6.

In my brief visit last week I saw abundant rockfalls in the canyons and fresh landslide scars on hillslopes. Others from the geologic mapping team report similar, widespread evidence for rockfalls.

I made a map of the campaign and continuous GPS field work.  Please let me know if I've left anything out.  The KML is posted at:  http://waddle.ucr.edu/kml/baja.kml

A GoogleMapApp is at: http://waddle.ucr.edu/~brad/baja

Brad

Luke Blair has provided an updated KMZ file with additional data layers, including surface faulting air recon photos, faulting and liquefaction field work results, GPS sites and initial InSAR results mostly from USGS investigators and collaborators.

Also, so that the pop-up photo previews and also full-resolution photos will work, go to the Google Earth 'general' preferences tab and check the following option: 'Allow placemark balloons to access local files and personal data' (and then click yes on the pop-up to allow access).

Revised! I had a sign error in my interferogram. The sense of motion was reversed.

I am attaching preliminary unwrapped Envisat interferogram from ascending track 306, using the pair from 2009/11/24 to 2010/04/13 and two frames. I attach both a map jpg and a kmz version. There may be errors in the unwrapping where the phase is not continuous, but it is clear that the east side of the fault moved down in addition to moving northwest.

http://igpp.ucsd.edu/~fialko/baja.html

(images are updated as more data are processed)

The ESA Envisat satellite acquired a SAR image on April 13 over nearly all of the Baja earthquake rupture and areas to the east. A quick-look of this ascending track 306 image is attached. The raw data should be uploaded to the GEO Supersite ( http://supersites.unavco.org/baja.php ) soon. Pre-quake Envisat scenes are already available.

The attached PDF file from Nancy King summarizes the USGS activities for the Baja earthquakes on 4/13/2010.

Note: After today Nancy will distribute daily reports only as new USGS activities occur. On Friday, April 16, she will distribute a summary report.

Brad

Unfortunately, strong winds due to the storms on Monday, April 12, caused problems for several UAVSAR lines that were acquired. We will probably need to refly those lines, perhaps on Thursday, April 14.