The binary data are available via anonymous FTP from the National Strong Ground Motion FTP-server:
https://ca.water.usgs.gov/nsmp/ in directory GEOS/SUP.
For further information on these recordings refer to USGS Open-File Report 88-700: Digital Seismograms of the Superstition Hills, California, Aftershock Sequence: November 24 to December 8, 1987; by M. C. Andrews, C. Dietel, T. Noce, E. Sembera, and J. Bicknell.
The GEOS Home Page is at /GEOS/geos.html
The URL of this page is /GEOS/SUP/superstition.html
e-mail: glassmoyer@usgs.gov
or address:
Gary Glassmoyer
345 Middlefield Road M/S 977
Menlo Park, California 94025