11.   For four days after the Landers quake, those instruments detected seismic activity far in excess of the usual.

12.   He tumbles down the side of the mountain and into a pit of molten lava formed from the volcano that has erupted because of all the seismic activity.

13.   Intensity is measured on the modified Mercalli scale, another measure of seismic activity.

14.   Just a few days ago, the government said that it planned to upgrade geological surveillance because of the increase in seismic activity.

15.   Levels C, D and E indicate increased seismic activity in a region.

16.   On the Richter scale, none comes close to the potential seismic activity this winter promises.

17.   One teacher explained westward expansion by having pupils make covered wagons while another had kids learn about seismic activity by making stilt houses in sand.

18.   On the World Wide Web, the US Geological Service provides a real-time, full-color map of seismic activity in the Bay Area.

19.   One display shows the last nine days of seismic activity in California.