 |
|
Earthquake faults lost and found @ the London `Catastrophes` conference
August 17, 2002Three great earthquakes during the winter of 1811-1812 struck eastern North America, causing widespread destruction in the northern Mississippi river valley, and even causing the Mississippi River to divert.
Though the estimated magnitudes of the earthquakes are between 7 and 8+, no definitive surface rupture has ever been identified. Instead, the seismic zone is delineated by microseismicity measured during the last several decades. However, it is unusual for shallow seismic events of this magnitude not to display any surface rupture - which has led Dr Peggy Guccione and colleagues to search for one.
New research by Dr Guccione argues that the Bootheel Lineament, a 135 km-long fault sub-parallel to the New Madrid seismic zone, caused the 1811-1812 earthquakes. Her detailed geological studies along the lineament support the hypothesis that the lineament is a surface rupture and that it is coincident with sediment liquefaction. More significantly, it appears that the structure not only ruptured in 1811-1812, but was responsible for at least two other rupture episodes.
If Peggy Guccione has found an earthquake fault, then Roy Schlemon appears to have lost one. Schlemon was responsible for the initial seismic hazard study for the Salt Lake City Convention Center, home of the 2002 winter Olympic Games. His geological studies revealed a previously unrecognised Holocene fault zone directly beneath the proposed Center. Radiocarbon and soil-stratigraphic dates show that a ~1.5 m vertical ground rupture event occurred between 7000 and 8000 years ago and that two further displacements of about 0.8m each took place after 6400 years ago.
The presence of Holocene faults would normally prevent construction of the Convention Center and adjacent buildings in accordance with Utah State law. But the potential social and economic consequences of law enforcement were so great that the governing agencies sought a "second opinion" about the origin and age of the fault. This second geotechnical review concluded that the observed displacements and vertical sand dikes were not site-specific Holocene faults, but rather were subsurface lateral spreads (liquefaction) ostensibly triggered by earthquake movement along the nearby (and active) Wasatch Fault.
Though debated vigorously in professional meetings, the "non-fault" hypothesis was ultimately accepted. Accordingly, the Convention Center is now built, operated well during the Olympics, and now annually hosts thousands of tourists, most of whom have no idea that they congregate on top of a zone characterized by repeated, Holocene ground failure.
The case of the `lost` earthquake fault of Salt Lake City illustrates that different interpretations of technical data are to be expected, especially when opposing opinions have major economic consequences. High-value, high-visibility projects invite potential "geopolitical manipulation" when short-term social and economic interests are at stake. Finally, legislating for public safety (e.g., setting up Holocene fault set-back zones) is one matter, but enforcing such legislation is another.
Geological Society of London, The
Earthquake Current Events and Earthquake News RSSA new approach in tsunami-early warning
The newly implemented Tsunami Early Warning System for the Indian Ocean, GITEWS, goes into operation today and with this, the system enters its final phase of optimisation.
Conclusive vote on cause of Indonesian mud volcano
A resounding vote of international petroleum geologists from around the globe concluded that the mud volcano was triggered by drilling of a nearby gas exploration well.
Stalagmites May Predict Next Big One along the New Madrid Seismic Zone
Small white stalagmites lining caves in the Midwest may help scientists chronicle the history of the New Madrid Seismic Zone (NMSZ) - and even predict when the next big earthquake may strike.
Researchers Discover Unexpected Properties of Materials in Lowermost Mantle
Materials deep inside Earth have unexpected atomic properties that might force earth scientists to revise their models of Earth's internal processes, a team of researchers has discovered.
May 2008 earthquake in China could be followed by another significant rupture
Researchers analyzing the May 2008 Wenchuan earthquake in China's Sichuan province have found that geological stress has significantly increased on three major fault systems in the region.
Major flooding risk could span decades after Chinese earthquake
Up to 20 million people, thousands of whom are already displaced from their homes following the devastating Chinese earthquake, are at increased risk from flooding and major power shortages in the massive Sichuan Basin over the next few decades and possibly centuries.
New NIST publication series addresses design of earthquake-resistant structures
Where can you find some of the latest insights in designing earthquake-resistant buildings joined together with current information on building codes?
Magmatically triggered slow earthquake discovered at Kilauea Volcano, Hawaii
Kilauea experienced a new dike intrusion, where magma rapidly moved from a storage reservoir beneath the summit into the east rift zone and extended the rift zone by as much as 1 meter.
Earthquakes may endanger New York more than thought, says study
A study by a group of prominent seismologists suggests that a pattern of subtle but active faults makes the risk of earthquakes to the New York City area substantially greater than formerly believed.
Severe, acute maternal stress linked to the development of schizophrenia
Pregnant women who endure the psychological stress of being in a war zone are more likely to give birth to a child who develops schizophrenia.
More Earthquake Current Events and Earthquake News Articles
 | Little Earthquakes : A Novel (Washington Square Press) by Jennifer Weiner This is the story of what comes after 'happily ever after' as three young wives make the journey into motherhood, and discover how it changes their sense of themselves and their relationships with friends and family. There's Becky, a plump, sexy chef, with an overworked husband, an adorable baby girl ...and the mother-in-law from hell. There's Kelly, an event planner who's trying to cram sixty... |
| The Coming Economic Earthquake by Larry Burkett | |
 | Earthquake in the Early Morning (Magic Tree House #24) (A Stepping Stone Book(TM)) by Mary Pope Osborne Jack and Annie travel back to the morning of the great San Francisco earthquake. While they are there, they meet a reporter and help get some kids to... |
 | The Coming Economic Earthquake: Revised and Expanded for the Clinton Agenda by Larry Burkett This edition of Burkett's bestseller has been expanded to include the Clinton agenda, and discusses the President's new budget package, the NAFTA proposal, and the national health care issue. Burkett is the bestselling author of The Complete Financial Guide for... |
 | Volcano & Earthquake (DK Eyewitness Books) by Susanna van Rose The most trusted nonfiction series on the market, Eyewitness Books provide an in-depth, comprehensive look at their subjects with a unique integration of words and pictures. DK's classic look at volcanoes and earthquakes, now reissued with a CD and wall... |
 | Apocalypse: Earthquakes, Archaeology, and the Wrath of God by Amos Nur, Dawn Burgess What if Troy was not destroyed in the epic battle immortalized by Homer? What if many legendary cities of the ancient world did not meet their ends through war and conquest as archaeologists and historians believe, but in fact were laid waste by a force of nature so catastrophic that religions and legends describe it as the wrath of god? Apocalypse brings the latest scientific evidence to bear on... |
| The Coming Economic Earthquake by Larry Burkett | |
 | Fundamentals of Earthquake Engineering by Amr Elnashai, Luigi Di Sarno Fundamentals of Earthquake Engineering combines aspects of engineering seismology, structural and geotechnical earthquake engineering to assemble the vital components required for a deep understanding of response of structures to earthquake ground motion, from the seismic source to the evaluation of actions and deformation required for design. The nature of earthquake risk assessment... |
 | Earthquake Terror (Puffin Novel) by Peg Kehret When Jonathan and his family go camping on Magpie Island, they look forward to a fun, relaxing weekend. But their fun quickly vanishes when Jonathan, his sister, Abby, and their dog, Moose, find themselves in the middle of a natural disaster. A devastating earthquake has hit, destroying their camper, knocking out the only bridge to the mainland, and leaving Jonathan, Abby, and their dog ... |
 | If You Lived At The Time Of The Great San Francisco Earthquake (If You.) by Ellen Levine This book takes you to San Francisco, California, shortly before, during, and after April 18, 1906. What would you have done when the quake... |
| © 2008 BrightSurf.com |