Aftershocks and Triggered Events of the
      Great 1906 San Francisco Earthquake,
      Based on Intensity Observations

      Aron J. Meltzner  (California Institute of Technology / U. S. Geological Survey)
      and David J. Wald  (U. S. Geological Survey)

      a presentation of ongoing research at the 2001 Annual Meeting of the Seismological Society of America

      The files below are available in PDF format; you will need Adobe Acrobat Reader (which you can download for free) in order to view them.


      PRESS RELEASE
      (18 April 2001)

      • Text
      • Figure 1
      • Figure 2


      PRESENTATION:
      SSA ORAL SESSION
      (18 April 2001)

      I have converted the slides I am using for my talk (along with some other slides that I will not have time to show) into PDF files.  The files below generally follow the order in which I will present them in my talk, but there are some exceptions.

      • Title
      • Disclaimer: Triggered Events
      • Outline of Talk
      • Methodology I: General Procedure
      • Methodology II: Grid-Search Algorithm
      • Aftershock on 18 Apr 1906
      • Aftershock on 23 Apr 1906 -- also see next two slides
      • Aftershock on 23 Apr 1906, version 2 -- with Sacramento Valley and Sierran Foothills observations removed, to show how much those points bias the solution. It is inferred that a lack of data from Mendocino County allows these distant observations to strongly bias the data. Both the magnitude and the location of the algorithm's solution are thrown out because the location is inferred to be far offshore (see next slide), and because of the biased results discussed here.
      • Map of the 1994 Mendocino FZ earthquake -- note the similarities between this event and the 23 Apr 1906 event. This, along with Abe's solution using Milne Instrument amplitude data, provided the constraints for the location and magnitude of the 23 Apr 1906 event.
      • Aftershock on 25 Apr 1906
      • Aftershock on 17 May 1906
      • Aftershock on 6 Jul 1906
      • Aftershock on 5 Jun 1907
      • Aftershock on 8 Aug 1907
      • Aftershock on 11 Aug 1907 -- this event appears similar to the event on 23 Apr 1906. Because of its inferred offshore location, the algorithm's solution was thrown out, and the location and magnitude were constrained based upon comparison to the 23 Apr 1906 event and other historic events.
      • Summary Map: Aftershocks
      • Triggered Event in the Imperial Valley, 18 Apr 1906
      • Triggered Event near Santa Monica Bay, 19 Apr 1906
      • Summary Map: Triggered Events
      • Regions used for Probability Calculation -- see discussion of calculation of probability under "OTHER DATA" below.
      • Number of Aftershocks: Expected vs. Actual
      • Map of the largest aftershocks of the 1857 Fort Tejon earthquake
      • Conclusions

      OTHER DATA
      (for eventual publication)

      • Latest Abstract (updated 10 Apr 2001)
      • Catalog of Reported Aftershocks (updated 6 Jun 2001)
      • Catalog of Reported Triggered Events (updated 6 Jun 2001)
      • List of Newspapers Checked (updated 6 Jun 2001)
      • Calculation of Probability that the "triggered events" occurred by coincidence


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      This page maintained by Aron Meltzner.
      Created 10 April 2001.
      Last modified 6 June 2001.