Seismic measurements can be made far from the site of an explosion.

The Soviet side has emphasized a different approach in which seismic measurements are made from outside the test site.

This, he says, would help improve the accuracy of seismic measurements.

The official said that more work needed to be done, including new seismic measurements to better map the fields.

Both sides also made seismic measurements far from the test site of tremors in the earth.

Seismic measurements showed the yield was closer to 140 kilotons.

The epicenters of over 4,000 earthquakes can be identified from seismic measurements taken since 1974.

Moscow has argued that seismic measurements based on vibrations in the earth are more accurate.

The detonation is intended to check the accuracy of the American scientists' seismic measurements.

Up to now, most verification has been done by "national technical means" - that is, through our own satellite observation or seismic measurements.

Magnitude measurements are more sophisticated now, reflecting a change in technology and experience with seismic measurements.

But seismic measurements of this kind lacked the sensitivity needed to identify and quantify the oscillations.

"Seismic measurements," Greenbaum said, staring at me again.

It said that seismic measurements can be improved so that they are just as good as the Corrtex approach.

Oceanic crustal thickness from seismic measurements and rare earth element inversions.

Under this approach, Corrtex measurements would only be taken to "calibrate," or check the accuracy, of seismic measurements.

They say that the Corrtex technique is accurate within 30 percent and that seismic measurements are generally less accurate.

An American seismic measurement is said to have put the blast at 139 kilotons, while on-site measurements put it over the 150-kiloton treaty limit.

These techniques include passive, resonance and active seismic measurements as well as gravity, electric and magnetic field mappings.

Based on distant seismic measurements outside the Soviet Union, the Russians are thought to have conducted fewer tests than the United States since 1963.

Data on Seismic Measurement Specifically, each side gave data on five of its nuclear tests that had yields of 100 to 150 kilotons.

This would be done by conducting only a limited number of Corrtex measurements at the Soviet site to calibrate seismic measurements, an approach supported by seismologists.

Paul G. Richards, an expert on seismic measurement, told the committee that the detection of few a Soviet tests over the 150-kiloton limit "does not directly indicate noncompliance."

The inner core is very difficult to study because of its remoteness, but recent advances in seismic measurement and computer modeling are beginning to unveil some of its secrets.

Under such an approach, Americans would take some direct measurements of Soviet tests to check the accuracy of seismic measurements that have been taken from outside Soviet territory.