by Jack Lee
Earthquake swarms are again hitting the Reno Nevada area and people want to know… is the big one approaching and is Chico in any danger?
The big shake would have a magnitude of 7.0 or greater and it is generally preceded by foreshocks. This has scientists thinking the big one could be coming very soon. Reno is ground zero for two deep faults that converge within the city limits. A deep fault is generally not visible from the surface, but its movement and power is every bit as dangerous as shallow faults.
Renos last major quake was in 1914 and it registered magnitude 6.4. Another quake occurred in 1869 near Reno and it was estimated to be about 6.7. Scientist believe earthquake swarms are a chain reaction and could trigger even bigger quakes. A costal quake in California could potentially send shock waves large enough to trigger a quake in Nevada.
The Sierra Nevada mountain range is getting taller as the Pacific tectonic plate dives under the Continental shelf causing extreme pressure that forces all land west of the Pacific Plate to move slowly to the northwest while all land east of it is pushed to the southwest. The current rate of slippage averages approximately 33-37 mm/year across California. The San Andreas Fault is our most active fault that runs about 800 miles through the middle of California.
A moderate earthquake has the effect of bleeding off some of the stress that causes a quake, but when colliding land masses shift and pressure builds without any quakes this is a good indication the big one is near, at least in geologic time, which could be anywhere from 20-100 years. The last prediction was the Parkfield earthquake in 2004, a magnitude 6.0 earthquake that struck California on the San Andreas Fault. This earthquake was originally expected in 1993.
Fortunately for Chico residents, there is no major fault activity nearby, except for the San Andreas which is about 140 miles away.