SEMINAR - Gary Peterson

The Cryogenic World of Triton
Dr. Gary Peterson
Department of Geological Sciences
San Diego State University
Wednesday, October 3rd CSL 422, 1pm

Triton is a large satellite in retrograde orbit around Neptune, the most distant (40AU) of the giant gaseous planets. Surface temperatures average about 40K and are cold enough to condense all of the heavier gases, including nitrogen. A pronounced tilting of Triton's spin axis gives rise to a strongly seasonal climate and the available imagery indicates a deteriorating south polar cap made of nitrogen. Evidently the released nitrogen is being transferred to the north pole and condensing there during the long winter season. Distant though the sun is, it evidently supplies enough energy to provide seasonal transfer of nitrogen much in the same manner that water alternately collects and melts at the earth's poles with the seasons. Triton has been resurfaced and shows little evidence of cratering. Probably the satellite has been heated, evaporating the surface ices and then the released gases have recondensed to provide a new surface. The energy source for the heating would appear to be tidal friction following capture by Neptune. The retrograde orbit of Triton would indicate capture and the lack of surface craters would suggest that the capture was a fairly recent event. Numerous irregular surface textures indicate repeated expansion and contraction and are compared with somewhat similar features on earth. Although the Earth/Triton surface features resemble one another, they would be composed of totally different material.

The Independent Planetologist - Lecture Service

The United States and Russia have long-term Solar System exploration programs. These undertakings have provided us with detailed imaging at a variety of scales of all planets and major satellites except Pluto/Charon. Many more NASA projects are currently underway. Landings on Venus (Russia), Mars (U. S.) and the Moon (Russia and U. S.) greatly enriched the available imagery with rock samples and/or analyses.

How is this voluminous information to be interpreted? The only way to comprehend most of it is to place it within the context of our understanding of the Earth. That field of endeavor is Planetary Geology. The persons most adept at interpreting features of other planets and satellites would be those who are most adept at interpreting similar features on the Earth.

Gary enjoys public speaking and consider it a service to the university and community. Planetary Geology has become a passion and he enjoys sharing that passion. Gary likes meeting people with similar interests and exchanging observations and ideas. Offering public lectures is an excellent way of accomplishing those goals.

Go to the Indepentent Planetologist Web Site for more information....

New Publication - Jared Morrow

Physical and chemical evidence of the 1850 Ma Sudbury impact event in the Baraga Group, Michigan

Peir K. Pufahl*,1, Eric E. Hiatt2, Clifford R. Stanley3, Jared R. Morrow4, Gabriel J. Nelson5 and Cole T. Edwards6

1 Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada
2 Department of Geology, University of Wisconsin, Oshkosh, Wisconsin 54901, USA
3 Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada
4 Department of Geological Sciences, San Diego State University, San Diego, California 92182-1020, USA
5 Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada
6 Department of Geology, University of Wisconsin, Oshkosh, Wisconsin 54901, USA

ABSTRACT

An ejecta layer produced by the Sudbury impact event ca. 1850 Ma occurs within the Baraga Group of northern Michigan and provides an excellent record of impact-related depositional processes. This newly discovered, 2–4-m-thick horizon accumulated in a peritidal environment during a minor sea-level lowstand that punctuated a period of marine transgression. Common ejecta clasts include shock-metamorphosed quartz grains, splash-form melt spherules and tektites, accretionary lapilli, and glassy shards, suggesting sedimentation near the terminus of the continuous ejecta blanket. Sedimentologic and geochemical data indicate that primary fallout from a turbulent ejecta cloud was reworked to varying degrees by an impact-generated tsunami wave train. Observed platinum group element anomalies (Ir, Rh, and Ru) within the Sudbury ejecta horizon are sufficient to suggest that the impactor was a meteorite. Documenting and interpreting the detailed characteristics of the Sudbury ejecta horizon in Michigan have yielded a fingerprint to identify this chronostratigraphic marker in other Paleoproterozoic basins. For the first time a foundation exists to assess the consequences of the Sudbury impact on Precambrian ocean chemistry and early life.

Geology; September 2007; v. 35; no. 9; p. 827-830; DOI: 10.1130/G23751A.1

SEMINAR - Avinoam Rabinovitch

Abstract

We have thoroughly studied the properties of electromagnetic radiation (EMR) emitted from fracturing materials. A model was suggested to explain these phenomena, which helped us relate EMR measured parameters with crack sizes and velocities.

Since EMR appears when fracturing only starts it might be useful as a tool to predict earthquakes in their latent period.

Avinoam's seminar title:
"Properties of electromagnetic radiation from fractures and the possibility of its use for earthquake forecast";
Wednesday the 19th of September 2007


Author of the
Tensile Fracturing in Rocks: Tectonofractographic and Electromagnetic Radiation Methods
Dov Bahat, Avinoam Rabinovitch, Vladimir Frid
Understanding tensile fracture in rocks provides an important key for the interpretation of many problems in structural geology. This book presents a multidisciplinary approach to tensile fracture in rocks (faulting is briefly addressed), starting with an introduction to fracture physics and progressing through tectonofractographic features, characterized both in experimental settings and in geological outcrops. Four examples of sedimentary rocks and two of granites have been chosen to demonstrate the principles and problems in fracture geology. Principles of fracture mechanics and rock mechanics are applied throughout the book, which also explores current understanding about electromagnetic radiation induced by fractures and how such radiation can be used to monitor and predict earthquakes and hazardous collapses in mines. The monograph serves not only as a manual on how to handle specific problems and their solutions in fractual geology but also as a starting point for researchers and graduate students interested in the field of rock fracturing.

Geol306 Structural Geology - La Jolla Fieldtrip Photos

Department Photo Gallery

The Big One - Earthquake risk in Southern California

The southernmost stretch of the San Andreas Fault is more than 150 years overdue for a large quake.

The San Andreas Fault stretches 800 miles from the Salton Sea at the southern end of California to the ocean just off Eureka in the north.
Skirting the foggy Bay Area, the fruitful heartland, and the bustling urban center of Los Angeles, it waits quietly.
For The Big One. An earthquake of 7.5 magnitude or greater that is certainly coming.

Experts say the normal probability for a large earthquake on any significant portion of the fault is once every 150 years; yet the southern portion has not “snapped” since 1690.
“We believe it’s accumulated more strain than other parts, like in San Francisco, where it broke with a large earthquake in 1906,” said San Diego State University seismologist Kim Bak Olsen.
The peacefulness, marked by smaller infrequent quakes, worries Olsen and his colleagues.
With extreme natural disasters – Hurricane Katrina, the Indonesian tsunami, the recent Peruvian earthquake – this calm before the storm can give rise to a lack of preparedness. The result is injury and death on a large scale when catastrophe strikes.

The prediction of natural disasters is still far from an exact science. However, Olsen and fellow SDSU seismologist Steven Day are working to learn more about the major scenarios the San Andreas is likely to produce, so Californians can prepare even if there is no answer to the question of when.
Their work may mean never having to say, “if only we had known,” when it comes to the powerful jolt the long-expected Southern California earthquake will deliver.

“Simulation helps us characterize the biggest events, which are also the rarest, the ones that really put a stress on society,” said Day. “We are trying to reduce that level of surprise.”
‘A gift’
Using extensive data on the geography of areas off of the fault, Olsen and Day have been working with the San Diego Supercomputer Center to create finely detailed video simulations of the fault’s most probable seismic activity and how these ruptures would unfold.
Olsen was the first person to do three-dimensional simulations of these kind 12 years ago while working toward a doctorate in geophysics at the University of Utah.

“It’s a relatively new thing to use supercomputers for these kinds of simulations, because they haven’t been around for that long,” Olsen said. “It’s like a gift for us seismologists; it’s a really big computational problem that hasn’t been possible to solve until now.”
Their latest round of simulations, dubbed TeraShake for the power of calculations, are so vividly detailed they reveal the direction, magnitude and duration of the shaking -- and some bad news for Los Angeles.
If the southern portion of the fault unzips from south to north, the very factors that have historically made L.A. such a desirable place to settle — majestic mountains and flat valleys, would cause it to shake violently for more than two minutes.
The energy from the quake would radiate outward from the likely epicenter near the Salton Sea, but not in stacked, even circles, as earthquakes are graphically conveyed on the evening news. Channeled toward L.A. by the San Gabriel Mountains, the waves would become trapped by the sedimentary basins situated underneath the city.
“The waves would bounce back and forth inside the basin, kind of like waves in a bathtub,” Olsen said. “This specific earthquake seems to be one of the worst-case scenarios.”

Other scenarios simulated in TeraShake include a north-to-south quake, in which Mexicali would experience the strongest shaking.
The trade-off
The information provided by TeraShake is potentially useful to engineers and policymakers in making decisions about new development in Southern California.
“Cities can take the information and basically not build hospitals and universities on those areas,” Olsen said.
If only it were that simple.

Because there is still no way to accurately predict the timing of natural disasters, politicians often find themselves torn between spending funds on catastrophic event preparation or on more clearly defined near-term needs.
According to Day, the results of this trade-off are particularly evident in Third World countries, where catastrophes of enormous magnitude are common. Funding preparedness means diverting money from urgent development projects.
“Our work doesn’t solve the political and economic problems entirely; it provides a scientific foundation for that,” Day said. “Ultimately, it depends on society’s willingness to pay the price for preparedness.”
Until major preparation measures don’t compete financially with other pressing public needs, Olsen and Day are doing what they can to define earthquake risks and raise public awareness for decision-makers and concerned citizens alike.
Even without sweeping changes to building codes and city planning, individuals can still take small – and potentially life-saving – measures to prepare for a major earthquake.
“If the public is aware of fault lines and their proximity to home or the workplace, they may be more likely to respond to the shaking of a large earthquake,” Olsen said. “Letting the public know they should secure bookshelves to the wall, and seek shelter under a solid table could save many lives during a significant shake.”
Olsen has even found a way to entertain as he educates. He contributed to the animated earthquake sequences for the IMAX Film “Forces of Nature” and the National Geographic film “Anatomy of an Earthquake.”
Related information

TeraShake
The San Andreas Fault
Southern California Earthquake Center
“Forces of Nature” IMAX film

Credits
Story by Lauren Coartney
Graphics by John Signer
Photographs by Tom Farrington, Instructional Technology Services
Banner photograph courtesy of FEMA News Photo
Edited by Coleen L. Geraghty

SDSU Marketing & Communications

Division of University Relations and Development

San Diego State University

5500 Campanile Drive

San Diego, CA 92182-8080

(619) 594-1476

Experts say recent quakes are wake-up call to county

By Robert Krier
UNION-TRIBUNE STAFF WRITER
September 11, 2007

The good news: The series of seven quakes that has rattled the region during the past week and a half probably doesn't mean The Big One is more likely to hit soon. The bad news: The Big One is probably not any less likely, either.

“If you had asked me two weeks ago, I would have said a 6.0 earthquake could hit today, or it might hit in 100 years,” said Patrick Abbott, a geologist with San Diego State University. “My answer today would be the same. This sheds no light. We just don't have short-term ability to predict.”

Abbott and other local seismologists hope the quakes, which have shaken residents but done no damage, serve as a wake-up call. The county is near major fault lines that could someday cause severe damage, and laced with lesser fault lines.

Five quakes, ranging in magnitude from 3.2 to 4.0, hit beneath the ocean floor off the county's coast between Aug. 30 and Sunday.

Two other quakes, a 4.7 on Sept. 2 and a 3.4 on Sept. 5, struck the Lake Elsinore area, about 70 miles north of San Diego. The larger Elsinore quake was felt by some residents in San Diego.

Quake clusters are unusual but not unheard of in San Diego. Abbott said a similar cluster occurred around San Diego Bay in 1985 and 1986. The largest quake of that series was a 4.7 five miles southeast of downtown on Oct. 29, 1986.

Graham Kent, a seismologist at the Scripps Institution of Oceanography, said there is less than a 1 percent chance the cluster of quakes could be foreshocks, precursors of a larger quake.

“Even if something is a foreshock, that doesn't mean the next one will be much bigger,” Kent said. “Typically, what you see is the first one is bigger, then the magnitude goes down.”

The offshore quakes occurred either along unnamed faults or what seismologists call “splays” – or branches – of the Coronado Banks fault off the coast. The underwater area is not well understood and mapped by geologists, Kent said.

“Out there, it's really beat up,” Kent said. “It's very complicated. There are dozens of faults.”
Abbott said the Elsinore and offshore quakes most likely are not directly related. He said usually it takes a much bigger quake to trigger movement on a neighboring fault.

The strongest quake ever in San Diego was in 1862. It was estimated to be 6.0. It damaged adobe buildings in Old Town and the old lighthouse at Point Loma. The largest quake since then was a 5.3 quake off the coast of Oceanside on July 13, 1986.

Two local faults are capable of producing quakes as large as magnitude 7.0, Kent said. The Rose Canyon fault, which runs through the middle of San Diego, is roughly parallel to the Coronado Banks fault offshore.

But Kent said the San Jacinto fault, a few miles west of the Salton Sea in Imperial County, and San Andreas fault just to the east of the sea, pose a greater risk. Those faults could cause quakes much greater than 7.0. They are close enough to San Diego to cause widespread damage and are overdue for a big quake. The southern stretch of the San Andreas has not had a major quake in nearly 300 years, and seismologists believe pressure is building.

The Marina District in San Francisco, which was devastated in the 1988 Loma Prieta quake, is about the same distance from the quake's Santa Cruz epicenter as San Diego is from the San Jacinto Fault, Kent said. Homes built on fill in San Francisco's Marina District crumbled during the Loma Prieta quake, and similar damage could occur to structures in San Diego if they are built on sandy bay soils.

Kent said the danger of local quakes is greater than most people realize, and many residents have not prepared their homes or stored emergency supplies.

“I don't think the average person in San Diego County is anywhere near as prepared as they should be,” Kent said. “People should go through their houses and figure out what will get thrown off the walls.”

The state's Earthquake Authority provides residential earthquake insurance and encourages Californians to reduce their risk, said Tim Richardson, acting chief executive officer. Only about 13 percent of homeowners in California have quake insurance.

Richardson said he does not expect the recent round of tem blors to spur a buying spree. That takes death and damage.

“Anything short of that doesn't seem to get people to do anything,” he said.

Union Tribune

Faculty/Staff Awards and Promotions

We are pleased to announce that the following faculty and staff were awarded and/or promoted for the 2007-2008 academic year.

Dr. Kim Bak Olsen
Promoted to Professor with Tenure

Dr. Rob Mellors
Promoted to Student Services Professional Academic Related III

Pia Parrish

25 Years of Service

Dr. John Cooper

We are sad to announce the passing of Professor Emeritus John Cooper. “Coop” was a legendary figure among geology students at Cal State Fullerton and a giant in the field of Sedimentary Geology. He died from a massive heart attack while taking his morning walk on Monday, Sept 3. He touched many lives and will be sorely missed.
Dr. Cooper’s research concerned stratigraphic analysis of Neoproterozoic and lower Paleozoic rocks in the southern Great Basin and Eastern Mojave Desert provinces. He was an expert in the use of sequence stratigraphy to investigate paleo sea-level, regional stratigraphic correlations, and continental margin evolution, and had supervised the theses of almost 60 students at Cal State Fullerton. John had served for several decades as a driving force in SEPM, the Society of Sedimentary Geology, serving as Treasurer and Managing Editor for the Pacific Section at the time of his death. In recent years, Dr. Cooper had led efforts to create a curatorial facility for the Orange County Archeology and Paleontology collection.
Dr. Cooper’s family will be holding a private funereal service and do not currently have plans for a public memorial. His wife has asked that interested friends, colleagues, and alumni be directed to make a donation in his memory to the Cooper Scholarship Fund in lieu of a public memorial service. Information on how to make a donation can be found on the Geology Department's web page: http://geology.fullerton.edu./
Source - David Bowman - CSU Fullerton

SEMINAR - Student Summer Experience

Jared Warner, Adam Cosentino, Melanie Biggs, Matt Burgess
San Diego State University

Wednesday, September 5th CSL 422, 1pm


Join us as department graduate students Jared Warner, Adam Cosentino, Melanie Biggs and Matt Burgess share their summer internship and research experiences.