NORTHERN CALIFORNIA – The Napa earthquake that occurred at 3:20 a.m. Aug.24, 2014, will certainly be remembered in the years to come.
The earthquake, described as a “sudden release of energy,” definitely shook many of us awake here in Lake County. Thankfully, little, or no damage was reported here.
I spoke with local geologist, Dr. Dean Enderlin (who was sorry he'd missed it!) about the quake.
When asked about the specific fault on which this earthquake occurred, he answered, “The epicenter was located along what appears to be a splay of the 'West Napa Fault,' which is known to be an active fault. This is the largest earthquake that has been measured along that fault zone. There was an M5.0 earthquake along it back in 2000 that also damaged parts of Napa, but not to this degree.”
Asked about the earthquake's aftershocks Enderlin stated, “Yes, aftershocks are continuing up to about M3.0. It takes time for the rock around the initial earthquake to adjust to the new stresses.”
Regarding the occurrence of other quakes this size or larger in Lake County, aside from the Loma Prieta 25 years ago, Enderlin said, “There was a large earthquake (actually a series of earthquakes) centered in Santa Rosa in 1969 that was felt over our region. It damaged buildings in Calistoga, and may have done a little damage in Middletown. The pair of earthquakes measured 5.6 and 5.7, and were centered on the Rodgers Creek Fault Zone (the largest and most dangerous fault zone in our area).”
The tool of choice for earthquake measurement is a seismometer. The word comes from the Greek, “seismos.” The term was first used by David Milne-Home in 1841.
Seismometers take the measurements of ground motions, and are utilized in both earthquakes and volcanic eruptions.
Seismologists generally record magnitude 5 or larger earthquakes. Those which are smaller than a 5 are measured by seismological observatories take their measurements from a scale called “the local magnitude scale” and are measured on a Richter scale.
The Richter scale, also known as the 'Richter Magnitude Scale', was designed from a base-10 logarithmic scale.
It was developed in 1935 by seismologists Charles Francis Richter and Beno Gutenberg, who were both based at the California Institute of Technology.
Kathleen Scavone, M.A., is an educator, potter, writer and author of “Anderson Marsh State Historic Park: A Walking History, Prehistory, Flora, and Fauna Tour of a California State Park” and “Native Americans of Lake County.” She also writes for NASA and JPL as one of their “Solar System Ambassadors.” She was selected “Lake County Teacher of the Year, 1998-99” by the Lake County Office of Education, and chosen as one of 10 state finalists the same year by the California Department of Education.
The Living Landscape: Earthquakes move and shake Lake County and the region
- Kathleen Scavone
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