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  • dshelly
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Hi all,

    This may be somewhat peripheral, but in case anyone is interested, it appears that this earthquake triggered some tremor (low frequency earthquakes, LFEs) along the San Andreas near Parkfield.   There was a small sequence mostly just north of Parkfield (-20 to -15 along-strike position on the attached plot) that started within minutes of the waves passing.  A much larger sequence that started ~10 hours later near Cholame (15-40 km along-strike position) may also have been triggered, as there was a bit of activity in this zone earlier, and these episodes are relatively rare (every few months).  These observations are not too surprising given the history of triggered activity in this zone (including apparent triggering by the 2007 M 5.4 Alum Rock earthquake), though the possibility of delayed triggering of a major tremor episode is interesting.

    More notes on the plot:  Along strike position goes from NW (top, -85 km) to SE (bottom, 65 km) - zero position is the town of Parkfield.  Color represents the estimated depth of the LFE family.  For more details see Shelly and Hardebeck, GRL, 2010 or Shelly et al., Nature Geoscience, 2011. 

    Best,

    David

  • scharer
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

     USGS group has been working on rapid acquisition and processing of aerial photos (here from CHP helicopter) for structure from motion digital terrain maps.  Examples attached.

  • herring
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

     Attached are co-seismic offsets from the PBO combined GPS analysis (Central Washington and New Mexico Tech) which used 2-days before the earthquake and 2 days after the earthquake and an updated MIT analysis which uses the same 2-day pairs plus the day of the earthquake split around the time of the earthquake.  Time series plots do not show large post-seismic motions compared the error bars on the daily position estimates.

    The attached PDF plot shows the results with the Green vectors being the JPL ARIA project results, red vectors PBO combined results and black vectors MIT results.  MIT results have error bars based on the RMS scatter of the phase residuals from each sites and the PBO results have a blend of this error model with a site independent  constant error model. 

    Tom Herring

  • baagaard
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    USGS is deploying additional instruments to densify the instrumentation in the Napa Valley. The temporary instruments are mostly Reftek 130s with Trillium Compact and Episensor sensors. A few are Netquakes (GeoSig).

    USGS deployed several instruments on Monday, densifying an existing east-west line running through downtown Napa. Most stations were deployed west of downtown near Browns Valley Rd. Station spacing is 1-2 km. None of these went in with telemetry, but we will be adding telemetry on Thursday.

    On Wednesday-Friday we are deploying 6 stations in the downtown area (one triangular array with ~250m spacing and one with ~800m spacing). We are also deploying an  8 km linear array along Jefferson St with about 1 km spacing. We expect these to all have telemetry.

    Rufus Catchings will be deploying three fault zone arrays using Texans to try and characterize the fault zone. One in the south in the vicinity of Cuttings Wharf along Bayview Ave - Las Amigas - Stanly; one in the north along and off of Redwood and Dry Creek roads, and one in Contra Costa county (to look for continuity of the fault zone across San Pablo Bay).

    Attached is a KMZ file with target locations (and installed locations from Mon).

  • hudnut
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Thanks, Mike. I'll have a look today. It sounds as if David Schwartz checked it on Sunday but that with the possibility of afterslip, it would be worth checking again.

    I have compiled a list of sites that I plan to check today as we try to work towards completeness, partly in order to fine-tune the area-of-interest for the airborne LiDAR.

         Ken

  • hudnut
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Mike,

    Tim & I checked it yesterday; see my reply to Sang-Ho's post.

         Ken

  • hudnut
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Thank you, Sang-Ho, it was helfpul. Yesterday, Tim Dawson (CGS) and I met at Napa County Airport to check the break from your InSAR for possible surface rupture.

    At the airport, we did find en echelon fractures of tectonic origin at one place. We then split up, with Tim checking south and me checking north from there along the tear in phase in the interferogram.

    Neither of us found other localities along that lineament with clear tectonic slip.

    On the basis of this new evidence, I am working on revising the area-of-interest polygon for use in the airborne LiDAR acquisition planning.

    Thank you for the timely InSAR results. It was very helpful.

    Regards,

         Ken

  • shyun
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Please find the COSMOS-SkyMed unwrapped coseismic interferogram data in the following link. Once the zip file is uncompressed, the README file has more details.

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/interferogram/...

    Hope this will be helpful for response and research.

    -- Sang-Ho Yun, JPL-Caltech ARIA project

  • aemorelan
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    Below is the link to a KMZ of surface rupture locations documented by the UC Davis team (myself and Chad Trexler). One CSV file contains the locations of each photo as well as a look direction. Another CSV contains a summary of the observations we made. The KMZ contains the sites that we visited, the data collected at each site, and a link to the rest of the pictures associated with the site.

     https://ucdavis.box.com/s/9zsz84638fp90grhikzx

    - Alex Morelan

  • shyun
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 29 weeks ago

    The links below lead you to unwrapped coseismic interferogram that shows the amount of displacement in the radar line-of-sight (see the colorbar on the top). This map gives you information on the extent and the size of the ground deformation. 

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/interferogram/ARIA_NapaEQ_CSK_D74_coseis_unw.kmz

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/interferogram/ARIA_NapaEQ_CSK_D74_coseis_unw.jpg

    Caption: Interferometric Synthetic Aperture Radar (InSAR) map of coseismic displacement in the radar line-of-sight (LOS, 29 degrees from vertical and roughly west) caused by the 2014/08/24 M6.0 South Napa Earthquake, California. Derived from COSMO-SkyMed data acquired on 2014/07/26 and 2014/08/27. Processed by ARIA team at JPL-Caltech in collaboration with the Italian Space Agency (ASI) and University of Basilicata. The epicenter indicated with the red star is from USGS NEIC. The blue line indicates the North Bay Aqueduct. COSMO-SkyMed data (c) ASI 2014.

    Contact aria@jpl.nasa.gov or aria@caltech.edu for more information.

    -- Sang-Ho Yun, JPL-Caltech ARIA project

  • barnhartwd
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    The NEIC has updated the event page on the USGS website to include recent slip distributions (one seismic from Doug Dreger, one geodetic from Bill Barnhart). 

     

    http://earthquake.usgs.gov/earthquakes/eventpage/nc72282711#scientific_f...

  • shyun
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    I am posting a damage proxy map of the affected areas. This zoomable map can help identifying areas to check for potential damage in person on the ground, with drones, or other airborne/spaceborne optical sensors.  

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/dpm/ARIA_CSK_DPMs_th0.02.kmz 

    Caption: Damage Proxy Map of the the 2014/08/24 M6.0 South Napa Earthquake, California. The red pixels represent areas of potential damage on the ground surface or buildings. There are two frames processed separately, and each frame boundary is indicated with red rectangle. Derived from COSMO-SkyMed data acquired on 2014/06/08, 2014/07/26, and 2014/08/27. Processed by ARIA team at JPL-Caltech in collaboration with the Italian Space Agency (ASI) and University of Basilicata. COSMO-SkyMed data (c) ASI 2014.

    Contact aria@jpl.nasa.gov or aria@caltech.edu for more information.

    -- Sang-Ho Yun, JPL-Caltech ARIA project

  • shyun
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    I am posting this again, as I cannot find the "edit" button I used to see. The COSMO-SkyMed coseismic interferogram URL has changed. The new URL is as follows. The zoomable wrapped interferogram can help locating surface ruptures. For example, there could to be one about 2.5 km east from the epicenter, running parallel to what Mike Oskin mapped. 

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/interferogram/...

    http://aria-share.jpl.nasa.gov/events/20140824-south_napa/interferogram/...

    Caption: Interferometric Synthetic Aperture Radar (InSAR) map of coseismic displacement (wrapped interferogram) in the radar line-of-sight (LOS, 29 degrees from vertical and roughly west) caused by the 2014/08/24 M6.0 South Napa Earthquake, California. Derived from COSMO-SkyMed data acquired on 2014/07/26 and 2014/08/27. One color cycle represents 1.56 cm of LOS displacement. Processed by ARIA team at JPL-Caltech in collaboration with the Italian Space Agency (ASI) and University of Basilicata. The epicenter indicated with the red star is from USGS NEIC. The white line indicates the North Bay Aqueduct. COSMO-SkyMed data (c) ASI 2014.

    Contact aria@jpl.nasa.gov or aria@caltech.edu for more information.

    -- Sang-Ho Yun, JPL-Caltech ARIA project

  • huynht
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    View and share information at: http://www.eqclearinghouse.org/2014-08-24-south-napa/

    Earthquake Data Map

    All information shared with the Clearinghouse is being collected in a Google Earth KMZ file. You can download the file here: https://drive.google.com/folderview?id=0B_skoYqbxPVHdlBiSm9IYkNpUDg&usp=sharing. There are many layers contained in this file and by default most are turned off.

    View Data Online

    You can also view the data online in the: ARCGIS DATA MAP

    Submit Data

    Add data while in the field using the Clearinghouse Field Notes Application and view Fieldnotes data map with photos.

  • oskin
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    The lineament visible on the radar east of the main rupture lies directly on the mapped trace of the airport strand of the west Napa fault. As far as I know this rupture has not been mapped in the field. I am not familiar with the COSMO-Skymed instrument. Looks like a little more than 1/2 fringe of displacement. Assuming pure RL slip, how much may there be? 

  • shyun
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    Good morning. I posted a kmz and a snapshot of COSMO-SkyMed coseismic interferogram at the following URLs. The zoomable wrapped interferogram can help locating surface ruptures. For example, there seems to be one about 2.5 km east from the epicenter, running parallel to what Mike Oskin mapped.

    http://aria-share.jpl.nasa.gov/events/20140824-napa/ARIA_NapaEQ_CSK_D74_...

    http://aria-share.jpl.nasa.gov/events/20140824-napa/ARIA_NapaEQ_CSK_D74_...

    -- Sang-Ho Yun, JPL-Caltech ARIA project

  • dreger
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    Thanks Alex

  • walls
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    5Hz GPS data for stations within 300km is available for 2014-08-24 (full day) at: ftp://data-out.unavco.org/pub/highrate/5-Hz/rinex/2014/236/

    1Hz 8/21 - 8/27 UTC (7 full days) is in the process of being downloaded.


    UNAVCO South Napa Earthquake Event Page: http://www.unavco.org/highlights/2014/south-napa.html
     

  • eqadmin
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    From Marjorie Greene (EERI) 8/26/14 17:57PDT:

    Just FYI--
    There will be a third briefing tonight. Then we will close the physical clearinghouse, although we know of a few more teams that will still be coming tomorrow--We will encourage people to contribute data and observations via the virtual clearinghouse.

    ___________________________________________________

    Our evening Clearinghouse briefing will take place at 6:00 p.m. Tuesday, August 26th at 3161 Jefferson Street in Napa.

    If you are not able to participate in person, we have set up a webex. The call in number for audio for the webex is the same as the call in number for the briefing

    callin briefing and audio for webex:
    866-828-5695
    passcode: 8077172

    -------------------------------------------------------
    Meeting information
    -------------------------------------------------------
    Topic: Clearinghouse Evening Briefing
    Date: Tuesday, August 26, 2014
    Time: 6:00 pm, Pacific Daylight Time (San Francisco, GMT-07:00)
    Meeting Number: 745 107 585
    Meeting Password: (This meeting does not require a password.)

    -------------------------------------------------------
    To start or join the online meeting
    -------------------------------------------------------
    Go to https://resources.webex.com/resources/j.php?ED=277401287&UID=497322317&R...

    -------------------------------------------------------
    Teleconference information
    -------------------------------------------------------
    call-in 866-828-5695
    password: 8077172

    -------------------------------------------------------
    For assistance
    -------------------------------------------------------
    1. Go to https://resources.webex.com/resources/mc
    2. On the left navigation bar, click "Support".
    To add this meeting to your calendar program (for example Microsoft Outlook), click this link:
    https://resources.webex.com/resources/j.php?MTID=m80dd10c791820180d53eb9...

    To check whether you have the appropriate players installed for UCF (Universal Communications Format) rich media files, go to https://resources.webex.com/resources/systemdiagnosis.php.

    http://www.webex.com

    Thanks

  • jhardebeck
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    Here's a text file with the locations.

  • eqadmin
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    near northern aftershock cluster.

    From Mike Oskin (UC Davis) 8/26/14 17:05 PDT:

    I received an email report of some possible surface rupture along Dry Creek road, about 3.5 km NW of Alston Park. This is well outside the zone of surface ruptures mapped thus far (that I am aware of). Could just be landsliding. However it is along the trace of the west Napa fault mapped by Wesling and Hanson, and its immediately updip of the cluster of aftershocks in this area. So I think that somebody should check this out when they get the chance. Email pasted in below. KMZ and google earth map attached.

    -Mike Oskin

    Hi Mike
    I've been following your twitter feed after the S.Napa quake, and I perhaps have some extra info for you.
    At 4155 Dry Creek Road, at my in-laws house, there is a large new crack that has appeared on the driveway, very approx 4m long and maybe 5cm wide at its widest point. I notice also that the neighbor to the immediate South on the road also has a long crack and mild "tenting" that has appeared across his driveway. I don't know how the faults run at this point.

    coordinates are approx: 38.3484591,-122.3573352

    Hopefully this can be of use in your research- I note that a lot of aftershocks were centered just behind this property but my knowledge doesn't permit me to know if that is relevant or not!


    regards

    Nick Guest

  • eqadmin
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    A short press release on aftershocks and revised probabilities:

    http://www.usgs.gov/newsroom/article.asp?ID=3981#.U_0hwkiRaRJ

  • aemorelan
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

     Doug,

    I have linked to a csv file with a list of our measurements that I have the most confidence in. The first ten rows are measurements along the main fault trace. The remaining four lie along the trace across the 500 meter jump to the east. All measurements are right lateral and in centimeters.

    https://ucdavis.box.com/s/a4ca3vfyt66cyxrvhu6l

    -Alex

  • eqadmin
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    From Jeanne Hardebeck (USGS) 8/26/14 15:29 PDT:

    Hi everyone,

    I've attached a revised set of earthquake relocations, based on our 3D seismic velocity model with relative locations refined using hypoDD. The main aftershock cluster in the mainshock hypocentral area (cross-section C-D) roughly defines a steeply SW-dipping structure. The recent aftershocks to the south of the mainshock are generally consistent with this apparent structure.

    The two northern clusters of seismicity (cross-section A-B) suggest a possible structure with a ~50° dip to the SW. I have been unable to obtain any good focal mechanisms for the events in these clusters to verify a dipping fault plane.

    I will post the updated relocation text files to the google drive site.

    Cheers,
    Jeanne

  • owen
    2014.08.24 - M6.0 South Napa Earthquake, California   2 years 30 weeks ago

    Am sending revised plot & table of offsets that cover a larger area around the earthquake.

    The offset table uses same data as earlier posted table - 7 days of daily positions from before the earthquake and a static position from ~13.5 hours after the earthquake (RED vectors in each plot)

    The "compare" plot shows results of differencing pre-earthquake position from daily solution from Sunday August 24 @ 5 pm - Monday August 25 @ 5 pm (UTC day 237). It indicates that there's no significant postseismic slip at this time and that increase in surface rupture reported from Sunday to Monday is likely due to slip occurring at very shallow depths. 

    Thanks,

    Sue, Angie, Zhen