Accessible Resources

Backprojection Results
Seismic Tomography Models
Processed Data
Historical Recordings and Digitization
Miscellaneous


Backprojection Results

Please keep in mind that the file sizes for some of the high-resolution animations can exceed 30 MB.

• April 11, 2012 Sumatra Earthquakes (Animations)
  • Mw 8.6 Earthquake -- 08:38:37 [Low Res.] [High Res.]
  • Mw 8.2 Earthquake -- 10:43:09 [Low Res.] [High Res.]
• March 11, 2011 Tohoku-Oki, Japan Earthquake
  • Mainshock animation (variable amplitude): [Low Res.] [High Res.]
  • Animation for the first 25 minutes (variable amplitude): [Low Res.] [High Res.]
  • Catalogue of events for the first 25 hours
• February 27, 2010 Maule, Chile Earthquake
  • Animation: [Low Res.] [High Res.]
  • Locations of peak high-frequency energy release
• March 28, 2005, Sumatran Earthquake
  • Animation: [Low Res.] [High Res.]
  • Numerical table of time-integrated relative high-frequency energy release as a function of position
• December 26, 2004, Sumatra-Andaman Earthquake
  • Animation: [Low Res.] [High Res.]
  • Numerical table of total (time-integrated) relative high-frequency energy release as a function of position

Seismic Tomography Models

During the last three decades, under supervision of Adam Dziewonski, Göran Ekström and Jeroen Tromp, several models of seismic velocity/density perturbations have been released by the Harvard Seismology Group. These models have provided valuable constraints about the Earth's interior. You can access some of these models by following the links below.

• Link to description of each tomographic model
• Links to download pages

Processed Data

While carrying out research, various types of processed data are generated. Some of these data are available.

• Group velocity maps
• Phase velocity maps
• Normal-mode observations

Historical Seismograms and Digitization

Harvard University, Department of Earth and Planetary Sciences maintains the HRV station located at the Adam Dziewonski Observatory (Oak Ridge, MA). The station is deployed in 1933, and is one of the oldest seismograph stations in the USA. The recordings of this station after 1972 are accessible online through IRIS. However, the earlier seismograms were not digitized or cataloged in a systematic manner.

Click on the year below to see image holdings and some of digitized data in SAC format.

1930's				1933	1934	1935	1936	1937	1938	1939
1940's	1940	1941	1942	1943	1944	1945	1946	1947	1948	1949
1950's	1950	1951	1952	1953

In addition to HRV records, short-period vertical analog seismograms from stations Hilo (HIL) and Uwekahuna (UWE) of the Hawaiian Volcano Observatory Network have been digitized for August 7 through 10, 1988. For description of how these data are used to determine relative time corrections between these two stations, see this page.

	08/07-08/08	08/08-08/09	08/09-08/10	08/10-08/11
HIL	JPG image SAC file	JPG image SAC file	JPG image SAC file	JPG image SAC file
UWE	JPG image SAC file	JPG image SAC file	JPG image SAC file

Note that there are multiple SAC files for a given image corresponding to individual traces. The SAC files have been gathered into a .tar file.


DigitSeis

DigitSeis is an interactive digitization software written in MATLAB that converts digital, raster images of analog seismograms to readily usable, discretized time series using image processing algorithms. The latest version of DigitSeis (v1.3) does not require MATLAB to be installed on the computer.

• DigitSeis v1.3 (March 29, 2018, Windows version added April 20, 2018)
  • Bundles
    • Complete package for Mac Users (includes Manual, DigitSeis v1.3, Example Image, 850 MB)
    • Complete package for Windows Users (includes Manual, DigitSeis v1.3, Example Image, 100 MB)
      Please note that this version has not been tested extensively, and there may be issues with saving the analysis. If you are using this version, please save frequently to files with different names.
  • Individual Files
    • Manual (pdf file, 30 MB, updated April 20, 2018)
    • DigitSeis v1.3 Package for Mac Users (zip file, 800 MB)
    • DigitSeis v1.3 Package for Windows Users (zip file, 10 MB)
      Please note that this version has not been tested extensively, and there may be issues with saving the analysis. If you are using this version, please save frequently to files with different names.
    • Example Image (JPEG file, use right mouse button to download, 60 MB)
  • Description of Changes (plain text file, 80 KB)

• DigitSeis v1.1 (June 01, 2017)
  • Manual (20 MB)
  • DigitSeis v1.1 MATLAB Codes (zip file, 130 KB)
  • Description of Changes (plain text file, 25 KB)
• DigitSeis version 0.53 with User's Manual (~3 MB)

Miscellaneous

• Thomas Lee's Undergraduate Bowdoin Essay (April 22, 2019)
• Sunyoung Park's Public PhD Defense (May 25, 2018)       Thesis (PDF file to be available in May 2019)
• Visit to the HRV station (April 10, 2018)
• Interns visit the HRV station (July 01, 2015)
• Eric Kiser's Public PhD Defense (April 27, 2012)       Thesis (PDF file)
• Geophysics at Harvard (published in 1939 or 1940)
• EPS166 class visits the HRV station (October 2nd, 2012). We owe special thanks to Dr. Joseph Steim for his through presentation about principles of recording ground motion, and deploying/operating a global station.
• Miaki Ishii's Thesis (PDF file)