The Independent Planetologist / Favored Lecture Topics

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The Independent Planetologist / Favored Lecture Topics:

"FAVORED TOPICS

Some lectures are one of a kind. Others are given over and over again, sometimes under different titles (in this list, only the latest title is indicated). The content of a talk can vary quite considerably, depending on the audience. Some talks tend to 'evolve' as they are repeatedly given. Listed below are some favored topics. The 'Planet Earth Series' of talks deal with earthly topics only. Click on the title and a list of venues will appear. (* indicates that the talk has been given 5 or more times, ** 10 or more times and *** 20 or more times.)

'PLANET EARTH SERIES'
'DOOMSDAY ASTEROIDS AND COMETS' **
'GEOLOGY: THE EARTH AS A PLANET'
'COLLISIONS OF COMETS AND PLANETS' **
'A FIELD TRIP THROUGH THE SOLAR SYSTEM'
'METEORITES AND OTHER SPACE DEBRIS'**
'SALT WEATHERING ON EARTH AND MARS'
'IMPACT STRUCTURES ON THE TERRESTRIAL PLANETS'
'BASALTIC FLOODING OF PLANETARY LANDSCAPES' **
'EVOLUTION OF THE GALILEAN SATELLITES OF JUPITER'
'THE SULFUR VOLCANISM OF IO'*
'EXPLORING THE MARTIAN DESERT' **
'THE GEOLOGICAL CASE FOR LIFE ON MARS' ***
'LOSS OF VOLATILE CONSTITUENTS FROM THE TERRESTRIAL PLANETS' **
'MARS: WHERE DID ALL THE WATER GO?' **
'EXPLORING THE LUNAR LANDSCAPE'*
'WHY IS MARS RED?' ***
'EUROPA: THE OTHER OCEAN'*
'IS THERE LIFE ELSEWHERE IN THE SOLAR SYSTEM?'*
'VENUS: EXPLORING THE INFERNO' **
'ATMOSPHERES AND OCEANS OF THE TERRESTRIAL PLANETS' **
'MERCURY: THE FORGOTTEN PLANET'**
'THE GREAT MARTIAN CLIMATE CHANGE'*
'THE PROBLEM WITH PLUTO'*
'THE CAPTURE OF THE MOON'*
'THE CRYOGEN"

The Great Southern California ShakeOut

At 10 a.m. on November 13, join millions of people throughout Southern California in the ShakeOut Drill, the largest earthquake preparedness activity in U.S. history!

Individuals, businesses, schools, colleges and universities will be spreading the word about earthquake preparedness throughout Southern California.

A week of special events featuring the largest earthquake drill in U.S. history, "The Great Southern California ShakeOut," has been organized to inspire Southern Californians to get prepared.

On Nov. 13, SDSU will activate its Campus Emergency Operations Center to participate in an exercise that will simulate the steps necessary to manage an incident such as an earthquake.

All members of the SDSU campus community are encouraged to periodically review earthquake preparedness information, including "Drop, Cover and Hold On" protocol, and help spread the word. Being prepared may prevent a disaster from becoming a catastrophe. Additional SDSU emergency preparedness information for students, faculty and staff may be found online.

Earthquake Simulations at SDSU
Kim Bak Olsen, Professor Department of Geological Sciences at San Diego State University, California discusses earthquake simulations.
Originally posted by SDSC on SDSC's CI Channel at: www.cichannel.org

SEMINAR - Aron J. Meltzner

Earthquake Recurrence and Long-Term Segmentation near the Boundary of the 2004 and 2005 Sunda Megathrust Ruptures

Aron J. Meltzner
Tectonics Observatory
California Institute of Technology

Wednesday, November 19th, 2008

Simeulue Island, off the west coast of northern Sumatra, straddles the boundary of the 2004 and 2005 Sunda megathrust ruptures. The 2004 and 2005 earthquakes nucleated northwest and southeast of Simeulue, respectively, and each ruptured bilaterally toward the 100-km-long island. Cumulative uplift was 1.5 m at both the northwest and southeast tips of the island but diminished toward the island’s center, where uplift was 0.5 m or less. Hence, although the 2004 and 2005 uplifts overlapped, there was an uplift deficit, or saddle, on central Simeulue.
Postseismic and long-term interseismic behavior, as revealed by coral microatolls, suggests that the Simeulue Saddle is more than a transient feature. The Saddle was partially, but far from completely, filled in by postseismic slip through 2007. As much as ~20 cm of uplift occurred in the Saddle region during both the Nov 2002 and Feb 2008 M ~ 7.3 earthquakes, although even those contributions fail to erase the deficit. Microatoll morphologies indicate that, averaged over decades and longer, interseismic strain accumulation rates are lower in central Simeulue than at the island’s ends.
U-Th dates of fossil coral microatolls suggest that northern Simeulue, which was uplifted in 2004, experienced an earthquake couplet or triplet in the 14th-15th centuries. Sites there experienced modest uplifts in ~AD 1393 and substantially larger uplifts in ~AD 1454. Some evidence exists for a third event, earlier in the 14th century, that uplifted northern Simeulue, but there is no evidence for prehistorical events after ~1454. The apparent lack of coral living on any of the reefs of northern Simeulue between ~AD 1454 and the early 20th century suggests that the reefs were above sea level during that entire period.
South of the Saddle, prior uplifts occurred in AD 1907, 1861, 1843, and around 1799. The 1861 earthquake appears to have been the closest analog to 2005 in size and extent, with 1843 and ~1799 being smaller, and with 1907 apparently occurring updip.
The spatiotemporal distribution of coral diedowns around Simeulue indicates that earthquakes have repeatedly propagated into the Saddle from both the north and the south, but there is no evidence of any rupture that has ever propagated through the Saddle. Altogether, observations of the behavior of central Simeulue during the recent and older earthquakes, and during postseismic and interseismic periods, suggest that the Simeulue Saddle is a poorly coupled segment of the megathrust that serves as a persistent barrier to rupture.