EXPLORATION - Controlled chemical explosions in Lake Superior


               UNITED STATES DEPARTMENT OF THE INTERIOR
                          GEOLOGICAL SURVEY
                      WATER RESOURCES DIVISION
                      WASHINGTON, D. C.  20242

                                                 October 7, 1964


GROUND WATER BRANCH MEMORANDUM NO. 65.6

To:       District Chiefs and Staff Officials (GW)

From:     Chief, Ground Water Branch

Subject:  EXPLORATION - Controlled chemical explosions in
                        Lake Superior

A series of controlled chemical explosions were made in Lake
Superior during the first week of October, 1964.  Detonations were
made on five successive days during the period October 1 through
October 8.

The purpose of the explosions is to obtain data relative to the
structure of the earth underneath the Great Plains and to study
the effects of this structure on the seismic waves generated.
Geologists hope to obtain a profile of a portion of the earth's
crust from Minnesota to Arizona from studies of resultant shock
waves which should be detected on seismographs as far away as
California.

We anticipate that the shock waves may cause water-level changes
in some of our observation wells.  Each district is requested to
check recorder charts carefully when they are changed and to send
a picture copy of charts showing an effect to Mr. R. C. Vorhis,
U.S. Geological Survey (GW), 19 Hunter Street SW, Atlanta,
Georgia.  If no changes in water levels are noted, you should send
this information also to Mr. Vorhis.



                                   (s) Gerald Meyer
                                   for O. M. Hackett

WRD Distribution:  A, B3, S3, FOL3, SL