The explosion showed up on seismic monitors and created a cavity 100 feet in diameter.

On the overhead map, seismic monitors were going wild in dozens of places across the planet.

The seismic monitors were completely off the scale in some places now.

Even the seismic monitors on the situation map showed everything in the green, all over the globe.

Schoolchildren are drilled about how to respond to earthquakes, and the Government has installed a nationwide system of seismic monitors.

And in one corner, Harland stood near the wrecked wall, nervously watching the readings of his portable seismic monitor.

I want to salvage my seismic monitor first.

Behind him, Mutchler huddled under an emergency blanket, engrossed in whatever data were still coming through to his portable seismic monitor.

Mutchler set down the seismic monitor and grabbed at the sides of the station access panel, wincing as he prepared to haul himself in.

After he had wormed himself in far enough to reach the communicator, she carefully handed the seismic monitor in behind him.