NASA Gives $400,000 Grant for Quake Study : Science: Money will help expand network of measuring stations to determine how seismic slip is spread throughout the region.

Southern California earthquake scientists have won a $400,000 grant from NASA to double the size of a network of measuring stations to determine whether there has really been, as some scientists surmise, a deficit of large earthquakes in the area over the last 150 years.

The grant will allow the installation of 15 stations from the Palos Verdes Peninsula to the Antelope Valley. The additional devices will facilitate precise measurements by the Global Positioning System of satellites on how the seismic slip is distributed through the region.

Scientists hope that the measurements will show whether a significant part of the annual average movement of seven or eight millimeters a year is by a seismic creep, or slip, or by means other than the jolts of big earthquakes.

This would mean that the stress built up over the years has been relieved somewhat by these smaller creeping motions and that consequently the risk of a great quake--to catch up with the amount of slip considered normal--may not be as great as some suspect.

In testimony before a congressional committee on March 2, Lucile M. Jones, a geophysicist with the U.S. Geological Survey, said that scientists who had studied 150 years of quake data in the Southland were concerned that there had not been enough quakes to explain all the movements noted along faults.

“Only one-third the number of large and major earthquakes” that might have been expected had occurred, Jones said, leading to fears of a “deficit” of quakes.

The new stations will be ready by the end of the year, and are the first of what scientists from the Jet Propulsion Laboratory, the Geological Survey, the Scripps Oceanographic Institution and the Southern California Earthquake Center hope will eventually be a $10-million network of 250 stations to measure strains throughout the Southland.

Ken Hudnut of the Geological Survey said Tuesday that the first conclusions drawn from data provided by the new stations should be available at the end of 1995.

“We will be able to measure within a millimeter what is happening in terms of movement between these stations,” Hudnut said. “If we find evidence of creep within the upper 10 to 15 kilometers beneath the surface, it will be taken as an indication that some of the strain is being relieved.”

However, he cautioned, findings of creep at lower levels could mean a loading of strain and an increase in the probability of large deep quakes.

Yehuda Bock of Scripps added that other key parts of the study will be to ascertain how the slip is distributed--geographically and over time.