Earthquake Rippling Across North America

[beecee]

https://www.sciencealert.com/epic-videos-show-the-july-4-earthquake-rippling-across-north-america

Videos Show The July 4 Earthquake Rippling Across North America
Before fireworks streaked across the skies of southern California on July 4, nature unleashed its own thunderous blast of energy: an earthquake.

The magnitude 6.4 temblor struck near Ridgecrest around 10:34 a.m. PT, cracking roads, bursting water mains, and toppling electrical power lines with its might.

A larger, 7.1 magnitude has since struck Southern California. Before that, the 6.4 quake was the most powerful to rattle the state in 20 years, and its shaking ended a five-year "drought" of earthquakes for California. Luckily, no deaths or major injuries have yet been reported.

As with all earthquakes, the Ridgecrest event was felt far beyond the borders of California – though not by people. Rather, incredibly sensitive devices called seismometers picked up the quake's rumbles from thousands of miles away.

Seismometers record the various ground motions of earthquakes, and a single station's data isn't all that interesting. Yet when many of the devices are sprinkled across a continent, they can be used to reconstruct a seismological event as it spreads, dissipates, and even bounces off underground structures.

As shown by a network of hundreds of seismometers called USArray, which is funded by the National Science Foundation, that seismic-wave data can look incredible.

"The ground motions can be captured and displayed as a movie, providing a visual demonstration of these often indiscernible movements," IRIS, a research group that studies seismological events and logs USArray data, says on its website. "The visualisations illustrate how seismic waves travel away from an earthquake."

more at link........

https://twitter.com/i/status/1146950304262475776

 

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They are calling this the " Ridgecrest event"....I presume Ridgecrest California, is on or near the San Andreas fault line? 

Edited July 7, 2019 by beecee

[Strange]

Just now, beecee said:

They are calling this the " Ridgecrest event"....I presume Ridgecrest California, is on or near the San Andreus fault line? 

No, it is a completely different fault. (And hence a completely different type of quake.)

[beecee]

Just now, Strange said:

No, it is a completely different fault. (And hence a completely different type of quake.)

Gee, quick off the mark this chilly morning Strange!!  

 

Thanks for the answer though. OK, how many bloody fault lines exist there? 

[Strange]

I learned all I know about this fault zone from this excellent Twitter thread: 

 

[OldChemE]

If you look at the history of earthquakes in Southern California you will see something very interesting.  The San Andres fault has a sort of "dogleg" or hockey stick bend in Southern California.  The pressure from the northward movement of the Pacific Plate, along the San Andres fault, pushes against the dogleg.  On a diagonal line roughly to the Northwest from this dogleg, there is a history of additional earthquakes, not on the San Andreas fault.  From an engineering perspective, it is as if the pressure at the dogleg is stretching the crust to the northwest, or maybe even (some day) forming a new fault line to the northwest branching off the San Andreas fault.  The Ridgecrest Earthquakes were on this diagonal from the San Andreas fault.

[beecee]

OK, thanks fellas...Obviously I'm not an inhabitant of California or North America, and thankfully I exist on and in a reasonable stable continent...not that we also do not have our own "natural" problems, particularly drought, living on the driest continent, other then Antarctica of course!!