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SDAG Monthly Meeting
Wednesday, September 20, 2017

Location: Geocon Incorporated - Upstairs Lounge
6960 Flanders Dr
San Diego, CA 92121
Tel: (858) 558-6900

FROM INTERSTATE 805: Take the Mira Mesa Blvd (Exit 27) exit. Head east on Mira Mesa Blvd for roughly 2 miles. Turn right onto Flanders Drive and Geocon will be on your left in about 0.4 miles.

FROM HIGHWAY 15: Take the Mira Mesa Blvd (Exit 16) exit. Head west on Mira Mesa Blvd for roughly 3.3 miles. Turn left on Camino Santa Fe and then turn right on Flanders Drive. Geocon will be on your right in about 0.2 miles.

happy hour
5:30pm -
Social hour  
Walawender Tavern (Beer & Wine)
*Geocon will be checking all Student ID's. No Alcohol can be served to anyone under the age of 21*
Menu: Mexican Buffet - Tacos and Enchiladas.
6:30pm -

Cost: $35.00 for non-members, $30.00 for members, $15.00 for students. if pre-registered by the deadline, $5 extra if you did not make a reservation. Click the SDAG member checkbox on the reservation form if you are a member.

Reservations: Make your reservation online by clicking the button below no later than NOON, Monday, September 18. RESERVATIONS CANNOT BE ACCEPTED AFTER Monday at noon. Late reservations/cancellations are preferred over walk-ins or no-shows. Fees payable at the meeting or pre-pay with PayPal.
As a new payment option, there will be a phone credit card reader at the meeting.

If you are a current SDAG member and are not getting e-mail announcements,
make sure the SDAG secretary has your correct e-mail address.

7:30pm -

Speakers: Drake Singleton and Dr. Tom Rockwell

"Late Holocene Earthquakes on the Rose Canyon Fault"

Abstract: We present the results of new paleoseismic trenches excavated across the main trace of the Rose Canyon fault (RCF) in Old Town, San Diego, to determine the timing of late Holocene earthquakes. The stratigraphy at the site consists of historical fluvial and alluvial fan deposits, several buried soil A horizons, massive silt strata, and older San Diego River gravelly secondary channel deposits. There is evidence for four large surface-rupturing events, as well as two smaller events, the youngest of which cuts the early historical living surface that contains glass, ceramics, cow bones, and a historical era foundation. This event is likely related to the 1862 San Diego earthquake, which had an estimated magnitude close to M6 and was described as "The day of terror in San Diego" in The Los Angeles Star. An even younger "cracking event" resulting in fissures through the historical alluvial deposits, and filled with historical-aged sand, suggests either a triggered event or minor creep. The possibility exists that addition smaller magnitude events have occurred on the RCF, but the stratigraphy at Old Town limits the resolution needed to distinguish evidence for every small surface rupture or cracking event. The four larger events produced substantially more deformation, and over a broader width of the fault zone, than the 1862 event: these events appear as displaced soil horizons, rotated silt beds, offset channel deposits, and fissures filled with overlying sediments. The youngest of these is immediately below the historical horizon and likely correlates with the most recent event recognized at multiple trench sites along the Rose Canyon fault in San Diego and dates to the past 400 years. The three older events have all occurred in the past 3,500 years, with the penultimate large event dated to about 1300 AD. The results of this paleoseismic study, combined with earlier results, indicate that the Rose Canyon Fault has sustained activity throughout the Holocene and into the Historical period. Comparison of paleoseismic results from the Newport-Inglewood fault (NIF) indicates that some RCF earthquakes have similar timing with NIF events, most likely indicating the occurrence of a sequence or cluster of events on the coastal system of strike-slip faults. The alternative explanation - large earthquakes rupturing both faults simultaneously - is unlikely when both the slip rate and recurrence intervals for these faults are considered.

Drake Singleton is currently a third-year PhD student in the Joint Doctoral Program in Earthquake Science and Applied Geophysics between San Diego State University's Department of Geological Sciences and University of California, San Diego's Institute of Geophysics and Planetary Physics at the Scripps Institution of Oceanography. He received a Bachelor of Arts degree in the Geological Sciences from the University of Colorado Boulder in May 2013. Prior to his arrival in San Diego, Drake worked as a well-site geologist for High Plains Consulting LLC monitoring daily operations and geologic conditions of natural gas drilling operations in Wyoming's Green River Basin. Drake's current research involves the use of applied geophysical techniques in combination with paleoseismic investigative methods to gain a better understanding of earthquake rupture characteristics and fault structure through structural stepovers and fault segmentation.

Dr. Thomas Rockwell is a nationally and internationally renowned paleoseismologist and structural geologist who has published over 135 articles in major international journals, coauthored a number of book chapters, published 50 papers in conference proceedings and guidebooks, and coauthored over 300 papers presented at professional meetings. Having served as Geology Group Leader for the Southern California Earthquake Center for many years, he is an expert on the tectonics and earthquake hazards of southern California and Baja California, has conducted extensive trenching programs to date earthquakes on faults in the western U.S., South and Central America, the Middle East and Asia, and routinely uses soil stratigraphy and geomorphology combined with various radiometric dating techniques to assess rates of fault activity, determine recency of faulting, and date past earthquakes. In the past decade, he has initiated a number of ground-breaking studies on fault zone architecture and processes in southern California with PhD students Ory Dor and Neta Wechsler, as well as with many MS-level students. New work on fault zone damage, pulverization, and fluid processes has resulted in over a dozen well-cited papers on this topic since 2006. His other research focuses on understanding earthquake occurrence in time and space. Current projects include the characterization of fault systems behavior by understanding patterns of past recurrence of large earthquakes on faults in southern California, northern Mexico, Panama, Argentina, Portugal, Spain, Turkey, India, and Israel. This work includes resolving information on slip per event, as it relates to understanding the controls on segmentation and rupture termination. Current work on fault zone processes initially focused on damage characteristics, but has shifted to the role of fluids and the processes that produce the damage. He has also worked extensively on the affects of tectonism on the landscape, and using geomorphology to constrain rates and timing of tectonic events. Included in this latter aspect is detailed mapping and dating of marine terraces along the west coast of North America and assessment of paleosea level during the late Quaternary.

Upcoming SDAG meetings - 2017

October 13 - 15: Julian Field Trip

November 14: 2nd Tuesday Pat Abbott - Phil's BBQ-Point Loma

December 13: 2nd Wednesday Tom Démeré - San Diego Natural History Museum

Meetings are usually scheduled for the 3rd Wednesday evening of the month. Meeting information on this website is normally updated the second week of the month.

If you have any information, announcements, ads or suggestions for an upcoming newsletter, please submit it to Ken Haase, (2017 SDAG Secretary). Any news regarding upcoming events that may be of interest to the Association or news of your business can be submitted. The submittal deadline for the next SDAG newsletter is the last Friday of the month.
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