Two earthquakes hit Crockett, California on Saturday afternoon.
Two earthquakes hit Crockett, California on Saturday afternoon.
Photo: USGS
The magnitudes of earthquakes measure the energy released by a tremor, but are not intended to calculate the intensity of jolts for people close to the epicenter. To measure the force felt by an earthquake on a person or something on the epicenter side, geologists use what is called the Mercalli Modified Intensity Scale. The following slides explain what it means when you see a Roman numeral representing the intensity of USGS reads and color coded intensity charts. Information from a USGS magnitude / intensity comparison. less
The magnitudes of earthquakes measure the energy released by a tremor, but are not intended to calculate the intensity of jolts for people close to the epicenter. To measure the strength of an earthquake felt at someone or … more
Photo: Vincent Maggiora / The Chronicle
Below a magnitude 3.0: Earthquakes at this level are generally considered level I Intensity. These are "not felt except by very few people in particularly favorable conditions," according to the USGS.
Below a magnitude 3.0:Earthquakes at this level are generally considered level I Intensity. These are "not felt except by very few people in particularly favorable conditions," according to the USGS.
Photo: USGS
Magnitude 3.0 to 3.9 –
Earthquakes at this level are usually level II. according to the USGS are "felt by some people at rest, especially in the upper floors of buildings "or level III, who wear"vibration similar to overtaking a truck. "
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Magnitude 3.0 to 3.9 –
Earthquakes at this level are usually level II. according to the USGS are "felt by some people at rest, especially in the upper floors of buildings "or level III, which
tremors at this intensity are often level IVwhich are widely felt but rarely cause serious damage or level v, which are felt by almost everyone and have the power to wake people up.
Magnitude 4 to 4.9 –
tremors at this intensity are often level IVwhich are widely felt but rarely cause serious damage or level v, which are felt by almost everyone and have the power to wake people up.
Magnitude 5 to 5.9 –
The USGS says level VI The intensity is where people start to get scared. By level VII we begin to see "considerable damage in poorly constructed or poorly designed structures".
Magnitude 5 to 5.9 –
The USGS says level VI The intensity is where people start to get scared. By level VII we begin to see "considerable damage in poorly constructed or poorly designed structures".
Photo: Robert Gauthier / LA Times
Magnitude 6.0 to 6.9 –
As evidenced by the Napa earthquake in 2014, level VIII Quake can destroy "chimneys, chimneys, columns, monuments" and walls.
By level IX many structures are ejected from the foundations and even well-designed buildings can be ejected. The 1989 Loma Prieta earthquake was part of this category.
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Magnitude 6.0 to 6.9 –
As evidenced by the Napa earthquake in 2014, level VIII Quake can destroy "chimneys, chimneys, columns, monuments" and walls.
By level IX many structures are overthrown from the foundation, and
… more
Photo: Scott Strazzante, The Chronicle
Earthquakes with a magnitude greater than 7.0 may range from level VIII up. The three highest X levels – where the masonry houses are largely destroyed, level XI – where bridges can go down, and level XII where "the damage is total" is the most intense. The 1906 San Francisco earthquake (damage shown above) was considered a level XI earthquake. less
Earthquakes with a magnitude greater than 7.0 may range from level VIII up. The three highest X levels – where the masonry houses are largely destroyed, level XI – where bridges can go down, and level XII where "damage is total" are … more
Two earthquakes hit Crockett, California on Saturday afternoon.
Two earthquakes hit Crockett, California on Saturday afternoon.
Photo: USGS
A magnitude 3.7 earthquake hits near Crockett, followed by a replica
The United States Geological Survey of America reported Saturday a magnitude 3.7 earthquake near Crockett, California, followed by a aftershock that shook the same area within 10 minutes plus later.
The first earthquake occurred at 11:56 local time, at a depth of 10 km.
The second, smaller earthquake was reported with a preliminary magnitude of 2.7 and was struck at 12:01.
There was no initial word on the damage or injuries resulting from these earthquakes. More information on this earthquake is available on the USGS event page.
Check out the latest USGS earthquake alerts, report the sensation of seismic activity and visit the interactive fault maps in the earthquake section.
