SCEC VDO Mini Grand
Challenge 2014 Visualizing Earthquake
Country
THE GREAT CALIFORNIA
SHAKEOUTSheila Bart, Greg Berger, Georgina Campos, Garland Chen, Jaquelyn Felix, Brandon Green
WHY IS CALIFORNIA REFERRED TO AS
“EARTHQUAKE COUNTRY”?
The frequency of earthquakes in California
- On average, there are approximately 30 earthquakes each day in California.
- Earthquakes of magnitude 6.0 and greater occur approximately every 5 years.
- In comparison to the central and eastern sections of the United States, California experiences a greater amount of seismicity.
Fault systems throughout California
- The San Andreas Fault system extends from northern California and continues south past the California border and into Mexico.
- In addition to the San Andreas Fault system, there are a number of other smaller fault systems throughout the state of California.
- The Los Angeles area itself has a number of faults that contribute to both small and relatively large earthquakes.
Works Cited
❏<earthquake.usgs.gov/earthquakes/states/seismicity>
❏Jones, L., Benthien, M. “Putting down roots in earthquake country”. Southern California Earthquake Center. 2011. <www.earthquakecountry.info/roots/contents.html>
❏Southern California Earthquake Data Center <www.data.scec.org/index.html>
WHAT TYPE OF FAULTS EXIST IN CALIFORNIA?
The answer may surprise you…
Normal Faults
What is it? Where is it?
◻Caused by extension◻Outward displacement
◻Death Valley⬜Horst and Graben⬜Elevation: -282 ft
Reverse Faults
What is it? Where is it?
◻Caused by compression◻Inward displacement
◻Transverse Ranges
Strike-Slip Faults
What is it? Where is it?
◻Displacement is parallel to fault strike
◻San Andreas Fault
Oblique Faults
◻A combination of strike-slip and reverse thrusting◻The most common type of fault
What is it?
Works Cited◻ Bartolomeo, Eleanor, and Nicole Longinotti. "Tectonic history of the Transverse
Ranges: Rotation and deformation on the plate boundary." . UC Davis, n.d. Web. 19 June 2014.
◻ Johnson, Jenda. "What are the 4 basic classes of faults?" Incorporated Research Institutions for Seismology. Web. 17 June 2014. http://www.iris.edu/hq/programs/education_and_outreach/animations/2.
◻ Jordan, Tom, Raymon Siever, and John Grotzinger. "Folds, Faults, and Other Records of Rock Deformation." Understanding Earth. New York: Frank Press, 2003. Print.
◻ "Lowest Places on Earth." Death Valley. National Park Service. Web. 17 June 2014.◻ "The San Andreas Fault." USGS. 17 January 2013. Web. 17 June 2014.
http://pubs.usgs.gov/gip/earthq3/safaultgip.html.
PLATE BOUNDARIES IN CALIFORNIA
Plate Composition
7 km (4 mi) thick Basalt More dense
Varies between 10 and 75 km (6 and 47mi)
Granitic rock Less dense
Oceanic Continental
Plate Boundaries
Two plates move apart in opposite directions
Think: conveyor belts Magma flows up from
the mantle where plates thin
Mid-ocean ridges
DivergentConvergent Plates pushing into
each other Continental →
Continental Continental → Oceanic Oceanic → Oceanic DENSITY Mountain formation Subduction
What kind of plate boundaries are found in California?
San Andreas fault zone → Transform Boundary
Pacific plate moves Northwest in relation to NA plate
Great 1906 earthquake that destroyed San Francisco
Transform Horizontal motion past each
other Mostly slide without creating
or destroying material Large earthquakes can occur
at transform plate boundaries
Works Cited Press, F., Siever, R., Grotzinger, J., Jordan,
T. H., 2003, Understanding Earth “Understanding Plate Motions.” United
States Geological Survey: http://pubs.usgs.gov/gip/ dynamic/ understanding.html, May 2012.
Explain how focal mechanisms
can be determined from earthquake data?
What are focal mechanisms?
What are focal mechanisms?
How are they calculated?
What does this all mean?Faulting geometry identification Look they’re beach balls!
compression vs. dilatation
Works CitedCronin, Vince, 2004, A Draft Pimer on Focal Mechanism Solution for Geologists, p. 1-14 USGS, 1996. “Focal Mechanisms.” Learn: Earthquake topics for Education. <http://earthquake.usgs.gov/learn/topics/beachball.php>.IRIS, 2012. “Focal Mechanisms Explained.” <http://www.youtube.com/watch?v=MomVOkyDdLo>. Merriam-Webster, 2014. “the Dictionary.”<http://www.merriam-webster.com/dictionary/dilatation> California Institute of Technology, 2014. “San Jacinto Fault Zone.” <http://www.data.scec.org/significant/sanjacinto.html> Springer Link, 2011. “Earthquake, Focal Mechanism.”<http://link.springer.com/referenceworkentry/10.1007%2F978-90-481-8702-7_158/fulltext.html> openSHA, 1980. “Strike, Dip, and Rake (focal Mechanism).” <http://www.opensha.org/glossary-strikeDipRake> Calvin College. “Eachquakes: A World in Motion. Recent Quakes, Calvin Seismograph…”<http://www.calvin.edu/academic/geology/seismology/>
ON WHICH FAULTS HAVE MAJOR EARTHQUAKES OCCURRED SINCE THE 1906 SAN FRANCISCO EARTHQUAKE?
What is a Major Earthquake?
Magnitude Intensity
Richter Magnitude
Moment Magnitude
measures the energy released at the source of the earthquake and it is determined from measurements on seismographs.
takes the amplitude and distances of seismograms and is known to underestimate the size of large quakes.
measures the strength of shaking produced by the earthquake at a certain location and it is evaluated from effects on people, human structures, and the natural environment.
Magnitude is related to the physical parameters that uses seismic moment (Mo), the force needed to generate the recorded waves, determines the energy released by the quake. MW = 2/3 log10(MO) - 10.7
What is a Major Earthquake?
San Francisco Earthquake 1906
5:12 AM - April 18, 1906Magnitude: 7.8Intensity: maximum intensity of XI was based on geologic effects, but the highest intensity based on damage was IX.
• Rupturing about 430 km or more to the northernmost of the San Andreas Fault
• The earthquake was felt from southern Oregon to south of Los Angeles and inland as far as central Nevada.
• Due to water pipe breakage, the water was shut off. Since there was no water, the fire got set off causing a large part of San Francisco to burn down.
Major Earthquakes since 1906
Date Earthquake Magnitude Faults 18 April 1906
San Francisco
ML 7.8 San Andreas
4 Nov. 1927
Offshore Lompoc
ML 7.1 Hosgri
21 July 1952
Kern County Mw 7.5 White Wolf
28 June 1992
Landers Mw 7.3 Johnson Valley,
Kickapoo, Homestead Valley, Emerson, and Camp
Rock 18 Oct. 1999
Hector Mine Mw 7.1 Hector Mine (Lavic
Lake) and Bullion
(Pisgah)
Faults Involved . . . Type of Fault Earthquak
e Fault Names
Right-Lateral Strike Slip
Landers
Johnson Valley, Landers,
Homestead Valley,
Emerson, and Camp Rock
faults
Hector Mine
Lavic Lake and Bullion
Reverse with some Left-Lateral
Kern County White Wolf
Reverse and Thrust Lompoc
Hosgri
Works Cited“Historical Earthquakes: San Francisco 1906.” USGS: Earthquake Hazards Program. 1 November 2012. Web.
16 June 2014. <http://earthquake.usgs.gov/earthquakes/states/events/1906_04_18.php>.
“Hector Mine Earthquake.” Southern California Earthquake Data Center. Caltech, 31 January 2013. Web.
16 June 2014. <http://www.data.scec.org/significant/hectormine1999.html>.
“Kern County Earthquake.” Southern California Earthquake Data Center. Caltech, 31 January 2013. Web.
16 June 2014. <http://www.data.scec.org/significant/kern1952.html>.
“Lompoc Earthquake.” Southern California Earthquake Data Center. Caltech, 31 January 2013. Web. 16 June 2014. <http://www.data.scec.org/significant/lompoc1927.html>. “Landers Earthquake.” Southern California Earthquake Data Center. Caltech, 31 January 2013. Web.
16 June 2014. <http://www.data.scec.org/significant/landers1992.html>.
“Measuring the Size of an Earthquake.” USGS: Earthquake Hazards Program. 1 November 2012. Web.
16 June 2014. <http://earthquake.usgs.gov/learn/topics/measure.php>.
Zoback, Mary Lou. “The 1906 Earthquake and a Century of Progress in Understanding Earthquakes and
their Hazards.” GSA Today April/May. 2006: 1-11. Print.
What is “Drop, Cover and
Hold on” and who is
participating?
ShakeOut: “Drop, Cover, and Hold On.”
11 million participants (US & other countries) 7,200,000 from California 830,000 from Japan
Who is Participating? K-12 School Districts Colleges and Universities Businesses Government Institutions
What is “Drop, Cover, and Hold on?”
Actions to take during an earthquake: DROP to the ground COVER by getting under a sturdy desk or
table HOLD ON to it until the shaking stops
Works Cited Shakeout – Drop, Cover, and Hold On:
http://www.shakeout.org/dropcoverholdon/
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