GEOPHYSICAL DATA

Information

Source

Obtainable

Comments

U.S. Geological

The most common types of

Water Supply Papers for an area can be

Survey Water Supply

geophysical data are

located by any of the computer searches or

Papers

available from seismic and

published indexes described in the first

resistivity surveys.

section of this paper.

In addition, the

USGS also publishes geophysical maps of

various types at relatively small scales for

many areas of the U.S.

Aeromagnetic maps

have been completed for much of the U.S.,

although the flight altitude of several

thousand meters and scale of 1:24,000 make

these maps too general for most site

specific work.

Well Log Libraries

Electric logs for many

The geophysical logs are indexed by survey

Electric Log

petroleum wells can be

section.

To obtain information on wells in

Services

obtained from one of

a given area, it is necessary to compile a

P.O. Box 3150

several well log libraries

list of the townships, ranges, and section

Midland, TX 79702

in the U.S.

numbers covering the area.

Tel: (915) 682 7773

Geophysical Survey

Specific geophysical logs

Proprietary geophysical data can sometimes

Firms

be obtained from private survey firms.

In

general, the original client must approve

the exchange of information, and preference

is given for academic purposes.

If the

information cannot be released, firms may be

willing to provide references to published

information they obtained before the survey,

or information published as a result of the

survey.

NOAA

NGDC maintains a computer

Site studies for many projects now require

National Geophysical

database which contains

information regarding the seismicity of the

Data Center (NGDC)

information on earthquake

region surrounding the site.

The National

Chief, Solid Earth

occurrences from

Geophysical Data Center (NGDC) of the

Geophysics

prehistoric times to the

National Oceanic and Atmospheric

325 Broadway

present.

Historic U.S.

Administration (NOAA) is a focal point for

Boulder, CO 80303

earthquakes are included

dissemination of earthquake data and

(303) 497 6521

for the period starting in

information for both technical and general

Fax (303) 497 6513

1638.

NGCD also maintains

users, except for information on recent

databases on other

earthquakes.

(Information about recent

parameters, such as

earthquakes can be obtained by contacting

topography, magnetics,

the USGS.)

gravity, and other topics.

For a fee, a search can be made for one of

the following parameters:

Geographic area (circular or rectangular

area)

Time period (staring 1638 for U.S.)

Magnitude range

Date

Time

Depth

Intensity (Modified Mercalli)

A4 9

November 1992