Researchers have recently found evidence that slow quakes appear to have preceded huge earthquakes in Chile and Japan, suggesting that the subtle quakes could be a precursor to a devastating one in the Northwest.

These should help scientists track ground movement that could precede earthquakes or eruptions, to map the spread and retreat of vegetation from spring to fall, and to track oil spills.

QuakeFinder has deployed a network of sensors that detect the electromagnetic effects the team believes precede major earthquakes.

The forecasting model does not include any geological information - like earthquake faults - or look at factors like bursts of electromagnetic radiation that some scientists say precede earthquakes.

The generation of new cracks might not unreasonably be assumed to precede major earthquakes.

Earthquake weather is a type of weather popularly believed to precede earthquakes.

Such close monitoring may allow scientists to detect pre-eruptive changes in volcanoes and movements in fault lines that precede earthquakes, providing an early warning of imminent natural hazards.