SDAG Monthly Meeting
Wednesday, February 17, 2016
Green Dragon Tavern and Museum
6115 Paseo del Norte
Carlsbad, CA 92011
Take I5 to Palomar Airport Rd east, to right turn (south) on Paseo del Norte, to right turn at second driveway to Green Dragon Tavern and Museum, north of Motel 6.
Menu: Lemon-Herb Chicken or Vegetarian Penne Pasta. Includes Caesar salad, roasted red potatoes, green beans with garlic sundried tomato butter, coffee, iced tea, and chocolate mousse for dessert. Cash bar.
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.
Make your reservation online by clicking the button below
no later than NOON, Monday, February 15.
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 DO NOT MAKE A RESERVATION, WE CANNOT GUARANTEE YOU A MEAL.
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.
Speaker: Dr. Keith Meldahl
"Surf, Sand, and Stone: How Waves, Earthquakes, and Other Forces Shape the Southern California Coast"
Southern California is sandwiched between two tectonic plates-the Pacific and North American plates-that grind right-laterally past one another.
During the transition from a former subduction boundary to today's transform boundary, the Pacific Plate captured large portions of crust that once belonged to the North American Plate.
The transfer of this kidnapped crust from one plate to the other created much of the fault-shattered geology we see today.
This process is ongoing, and earthquakes and tsunamis are expected consequences.
In recent geologic time, sea level changes triggered by Pleistocene glacial-interglacial cycles have profoundly shaped the coast.
The up-down yo-yoing of sea carved and filled rivers valleys to form coastal lagoons, and hacked flight-of-stair-like marine terraces into tectonically rising blocks of coastal bedrock.
Humans have now become a geologic force along the coast.
Constructions such as river dams, seawalls, and jetties have put many local beaches into sand deficits, necessitating artificial replenishment to maintain beach size and reduce bluff erosion.
The reservoirs of some Southern California river dams are now so sediment-clogged that they serve no water storage purpose; yet the dams still block sand from reaching downstream beaches.
Seawalls, built to hold the line against bluff erosion, deny a basic geologic reality: our coastal bluffs exist because of hundreds of feet of natural landward retreat that dates back to the rise of sea level after the Last Glacial Maximum.
Surfing is Southern California's iconic sport, thanks in part to three major Pacific storm centers that send ocean swells here at different times of year.
Offshore islands and banks dampen arriving swells, creating swell shadows on some parts of the mainland, while opening swell windows in other areas.
Southern California's most famous surf spots, such as Cortes Bank, Black's Beach, Trestles, Malibu, and Rincon Point, exist because of the way that seabed topography bends and focuses the energy of arriving swells to create high-quality surfing waves.
Surf, Sand, and Stone is a book for non-specialists interested in the geologic and oceanographic processes that have created the Southern California coastline.
Copies of the book will be available for sale at the meeting.
Keith Meldahl is a professor of geology and oceanography at Mira Costa College, where he has taught since 1997.
He is the author of two popular books about the geology of the western US, Hard Road West (University of Chicago Press, 2007) and Rough-Hewn Land (University of California Press, 2011).
Keith earned his BA in geology from the University of Chicago (1983) and his MS (1986) and PhD (1990) in geology from the University of Arizona.
For fun, he plays guitar in a classic rock band, and enjoys bodysurfing, camping, and exploring outdoors.
Upcoming SDAG meetings - 2016
February 17: Keith Meldahl - Surf, sand and stone; how waves, earthquakes and other forces
shape the Southern California coast
March 16: Diana Lindsey - The Geology of a Portion of Africa
April 20: SDAG Student Scholarship Presentations
May 18: Markes Johnson - Gulf of California Coastal Ecology and Geology: Insights from the Present and Patterns from the Past
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
Rupert Adams, (2015 SDAG Secretary).
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The submittal deadline for the next SDAG newsletter is the last Friday of the month.