By now, most of us are familiar with the basic mechanics of earthquakes: there are cracks in the earth's crust, and movement along those cracks or faults makes for quakes. Scientists expect a major earthquake along the Cascadia Subduction Zone, and it may give a warning. Research shows swarms of small quakes may act as harbingers of much bigger seismic events.

Three months have passed since the deadly Camp Fire devastated towns in the mountains of Butte County, Calif., leaving residents with burned-out properties covered with potentially toxic debris. In the mountain hamlet of Concow, one ridge over from Paradise, folks say they're used to wildfires and cleaning up after them. They load up a pickup a few times and haul the debris away to the dump. At least that's how they remember it being in 2008 after the last wildfire; but this time around, the...