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SDAG Monthly Meeting
Wednesday, April 16, 2014

Location: Emiliano's Mexican Restaurant
6690 Mission Gorge Road,San Diego, CA 92120
(619) 284-2460

Directions: On Mission Gorge Road overlooking Admiral Baker golf course. You will probably have to drive about 1/2 mile past the restaurant and make a U-turn to get into the parking lot.
happy hour
5:30pm -
Social hour  
Cash Bar.
6:30pm -

Menu: Mexicano fantastico. Beverage station.

Cost: $30.00 for non-members, $25.00 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, April 11th. 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 -

Student Scholarship Talks

Speaker: Cornelius Harris (USD Undergrad)

"Naturally Occurring Concentrations of Seventeen Metals in the Bay Point Formation, San Diego, California"

Abstract: The geogenic concentrations of metals in the native formations of San Diego County is poorly understood and poorly represented in the literature. The concentrations of metals in soils is a fundamental criteria regarding remediation and determining disposal options for soils removed from contaminated or potentially contaminated properties in San Diego County. We present the results of over 200 in-situ geogenic soil samples from the Bay Point Formation of San Diego, California. The location for this project is in downtown San Diego and consists of an area of approximately 1.3 square miles (3.34 km) between latitude lines 32° 43' 30" N and 32° 42' 30" N, and longitude lines 117° 09' 00" W and 117° 10' 30" W. All of the soil samples were analyzed for metals following EPA 6000 / 7000 Series Methods on an ICP Mass Spectrometer. The 95% UCL for 17 metals was calculated using the statistical software package ProUCL.

Our results show the Arsenic concentrations detected during this study exceed commonly used health risk soil screening levels and other risked-based corrective action guidelines utilized by many regulatory agencies in California. Additional research is needed to assess the bio-availability of the Arsenic, the potential impact to human health and the environment, and the impact these results may have on current regulatory thresholds for assessing soils on residential and commercial properties in San Diego County.

Further research is currently underway to identify the range of concentrations of metals in additional formations throughout the San Diego Embayment (e.g. San Diego Formation, Torrey Sandstone, Mission Valley Formation, Scripps Formation). Additional data is also being collected throughout the mountains and desert regions so that a comprehensive study of the concentrations of geogenic metals in San Diego County sediments can be published.

Speaker: Brian Rockwell (SDSU Grad Student)

Non-central principal component analysis of geochemical data and clay mineralogy from the San Jacinto fault in southern California: a new method to assess alteration intensity in fault zones

Abstract: A new method to analyze geochemical data and derive translation invariant alteration intensity factors within the framework of the fault zone architecture model was applied to the Clark strand of the San Jacinto fault in southern California. The new method utilizes non-central principal component analysis to derive and asses the statistical significance of compositional linear trends. Alteration intensity factors are then derived from orthogonal projection onto the calculated compositional linear trends. PC1 derived from non-central principal component analysis explains 99.7% of the simplicial variability of the spread of A-CN-K data about a calculated compositional linear trend. Results from a one-way ANOVA indicate that at least one significant difference across the group of means of alteration intensity factors are statistically different at the 95% confidence level (omnibus p = 0.0001). Post hoc routines indicate that the mean of the alteration intensity factors for the fault core are different than the means obtained from the transition and damage zones. In contrast, at the 95% confidence level, the means of the transition and damage zones are not statistically distinguishable. The results of XRD work completed during this study revealed that the < 2 micron fraction is composed primarily of illite/smectite with ~15% illite in the damage zone, of illite/smectite with ~30% illite in the transition zone, and of discreet illite with very minor smectite in the fault core.

Based on the above results, it is speculated that when fault zones are derived from tonalitic wall rocks at depths of ~0.4 km, the onset of illite/smectite to illite conversion will occur when alteration intensity factors exceed 0.20 ± 0.12, the average alteration intensity factor calculated for the transition zone. Under such conditions during repeated rupturing events, acidic fluids with elevated temperatures (>= ~125° C) are flushed through the fault core. Over time, the combination of shearing, fragmentation, and relatively elevated temperatures eventually overcomes the kinetic barrier for the illite/smectite to illite transition. Such settings and processes are unique to fault zones, and as a result, they represent an underappreciated setting for the development of illite from illite/smectite.

Speaker: Luke Weidman (SDSU Undergrad)

Landslide Hazard Analysis and Mitigation for Sepanjang Village, Central Java Indonesia

Abstract: This study is based on 8 weeks of field work and study in Indonesia during summer 2013 participating in a student-based community service program run by Gadjah Mada University. The study was focused on the village of Sepanjang in Central Java which is located on the southwestern flank of Mount Lau, a dormant stratovolcano. The project was a landslide mitigation effort focused on the improvement of landslide education for the village by creating an up to date field map that provided the village with locations and descriptions of landslides, potentially dangerous areas, evacuation routes, and general meeting areas during emergencies.

Indonesia is a massive archipelago that contains 18,000 islands and is located on the southern lobe of the Eurasian plate. Subduction of the Australian plate underneath the Eurasian plate bounds Indonesia to the west and south, and subduction of the Pacific plate underneath the Eurasian plate takes place to the east. These tectonically active zones are characterized by intense volcanism and seismicity that have a continuous effect on the topography. Annual rainfall for Java is 69.1 inches per year, which is almost seven times that of San Diego, CA. These factors contribute heavily to the susceptibility of landslides and result in the imminent danger to people and infrastructure. These susceptibilities were produced by measuring the physical properties of the landslides, including slope, thickness of soil, amount of vegetation, land use, and existing signs of recent movement. Assistance from other Gadjah Mada students allowed for both dispersal of the susceptibility map to local leaders and rescue teams, as well as providing villagers with landslide education and ways to notice and respond to signs of land movement.

Active landsliding is widespread in the area of the village and presents hazards to people and property. The impact of human development on the landscape plays a significant role in producing landslide hazards in the area that include road construction, agricultural terracing, and quarrying for building materials. This study brought to light the lack of landslide understanding in rural Java and the need for educational services to help local villagers see, prepare for, mitigate, and respond to landslide disasters.

Upcoming SDAG meetings - 2014

May 21: Mike Pallamary - Historical Maps and SoCal Mapping Mysteries

June 18: Eric Drummond, Ice Cold Gold in Greenland - El Adobe Restaurant - joint meeting with SCGS

July 16: Rob Anders, USGS - San Diego Coastal Aquifer Geochemistry

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 Matan Salmon (2014 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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