First, all the active faults in Southern California,
such as the San Andreas and the San Jacinto faults, were
examined. Then, the fault lines were displayed via a 3D
imaging program called Fledermaus. Afterward, the
most significant earthquakes that occurred on each fault
were studied. The data showed that the largest recorded
earthquakes in Southern California were the Landers
earthquake and the Hector Mine earthquake. Lastly, the
magnitudes and depths of each earthquake since 1982
were reseached and plotted.
Southern California Fault Map
Key for the Faults
SA = San Andreas
Rn = Rinconada
Hos = Hosgri
SJ = San Juan
Oz = Ozena
BP = Big Pine
PM = Pine Mountain
SY = Santa Ynez
SC = San Cayetano
SS = Santa Susanna
Oak = Oakridge
MC = Malibu Coast
SM = Santa Monica
SN = Sierra Nevada
WW = White Wolf
Gar = Garlock
Bw = Blackwater
Ha = Harper
Lck = Lockhart
Hel = Helendale
Ln = Lenwood
Cal = Calico
Ps = Pisgah
Lud = Ludlow
Bul = Bullion
PtM = Pinto Mountain
Blu = Blue Cut
SG = San Gabriel
SiM = Sierra Madre
PV = Palos Verdes
N-I = Newport-Inglewood
Wh = Whittier
SJc = San Jacinto
Ban = Banning
HS = Hot Springs
Els = Elsinore
SsH = Superstition Hills
SsM = Superstition Mountain
Imp = Imperial
Total Number of Earthquakes
Magnitudes vs. # of Earthquakes
60
# of Earthquakes
50
40
30
20
10
0
5
6
7
Magnitudes
•57,973 total earthquakes from 1982-2005
•49 earthquakes >M5
•8 earthquakes > M6
•2 earthquakes >M7
•The two earthquakes greater than M7 were the Hector Mine and Landers earthquakes
Date of Earthquakes vs. Magnitude of
Earthquakes
Date vs. Magnitude
8
7
6
Magnitude
5
4
3
2
1
0
1/1/1975 12/1/1976 11/1/1978 10/1/1980 9/1/1982 8/1/1984 7/2/1986 6/1/1988 5/2/1990 4/1/1992 3/2/1994 1/31/1996 12/31/199 12/1/1999 10/31/200 10/1/2003
-1
7
1
Date
•The magnitudes of most earthquakes are within the range of 0-4
•As the years progress, more earthquakes are recorded as technology improves
Magnitudes
M (3-4)
M (1-3)
M (4-5)
M (7-8)
M (6-7)
M (5-6)
Date of Earthquakes vs. Depth of
Earthquakes
Date vs. Depth
45
40
35
Depth (km)
30
25
20
15
10
5
0
1/1/1975
9/9/1988
5/19/2002
Date
•1977-1988: the earthquakes were all between the depths of 17-21 km
•1988: the deepest earthquake occurred
•After 1988, depths dropped
•1999: depths rose again due to the Hector Mine earthquake
Years
1986-1990
Hector Mine Earthquake
(1999)
Magnitudes
M (3-4)
M (1-3)
M (7-8)
M (4-5)
Landers Earthquake
(1992)
M (6-7)
M (5-6)
•
•
•
•
•
•
•
Struck on the eastern side of
the San Bernardino Mountains
at 4:57 A.M on June 28, 1992
Magnitude of 7.3
Largest earthquake to hit
Southern California since the
Kern County earthquake in
1952 with a magnitude of 7.7
The type of faulting was rightlateral strike-slip
One person killed, 25 people
seriously injured, 372 people
treated for earthquake related
injuries
Total property damage value
was about $56 million
Occurred on the Lenwood fault
• Occurred 2:46 A.M on
Saturday, October 16, 1999
• The largest earthquake
since the M7.3 Landers
earthquake
• Occurred on the Calico
fault
• Magnitude 7.0
• Only lasted about ten
seconds
• The type of faulting was a
right-lateral strike-slip
In conclusion, Southern California is
located on one of the most active faults,
the San Andreas Fault. Also, the largest
earthquakes ever to occur in Southern
California are the Landers (1992) and
Hector Mine (1999) earthquakes. Although
we do not know when the big one will hit
Southern California, our technology will
keep improving to make our cities safer
and to make sure everyone is prepared.
Works Cited
• http://geology.about.com/library/weekly/aa111499a.htm
• http://seismo.berkeley.edu/annual_report/ar99_00/node20.html
• http://www.scienceblog.com/community/older/2003/A/2003595
5.html
• http://earth.esa.int/applications/data_util/SARDOCS/spacebor
ne/Radar_Courses/Radar_Course_III/landers_earthquake_sou
th_california.htm
• http://quake.usgs.gov/info/listen/combination.html
http://www.nature.com/nature/journal/v411/n6836/abs/411462a
0.html
• http://www.everything2.com/index.pl?node_id=1322804
Acknowledgements:
We would like to thank our instructors, Dr. Benson Shing,
Bridget Smith, & Andreas Stavridis for teaching us about the
structures during earthquakes and geophysics of earthquakes, Jon
Deck and Allison Jacobs for helping us every step of the way, and our
teacher fellow, Jerry Lederman, for always being there for us.