Information

Source

Obtainable

Comments

Geomagnetism

GEOMAG contains current

Current or historical values back to 1945

(GEOMAG)

and historical magnetic 

can be obtained over the telephone at no

Branch of Global

declination information

charge by calling (800) 358 2663.

To access

Seismology and

for the United States.

It

the full program via modem, contact the

Geomagnetism

provides historical and

listed office for hook up instructions.

USGS

current values of

There is no subscription fee.

Box 25046

declination.

Federal Center

Mail Stop 968

Denver, CO 80225

(303) 273 8440 or

(303) 273 8441

A4 10

November 1992