January 25, 2007

The Hidden World of the Golden Gate

How tides, currents, and humans have created an array of sea-floor features

• A century of technical advances allow scientists to identify and visualize spectacular sea-bottom features
• Recent collaborative research outside the Golden Gate found that 100 million cubic yards of sediment disappeared in the past 50 years
• Swift, powerful tidal currents have scoured the Golden Gate down to bedrock and moved massive amounts of sediment
• Giant sand waves near the Golden Gate reach 30 feet in height and more than 700 feet in wavelength
• Why is the sediment in this area mostly from local sources, while farther out to sea are masses of sediment derived from erosion of the Sierra Nevada?

February 22, 2007

Riding the Storm

Landslide Danger in the Bay Area Hills

• A catastrophic 1982 rainstorm triggered 18,000 landslides in the Bay Area, claiming 25 lives and causing $66 million in property damage
• The combination of steep slopes, weak rocks, and intense winter storms make Bay Area uplands an ideal setting for landslides
• Landslides include both swift, potentially deadly debris flows and slower, but destructive deepseated slides
• Learn what USGS scientists have discovered about landslide dynamics and which slopes are most susceptible to sliding
• Hear the devastating stories of Bay Area residents affected by landslides and learn to recognize the danger signs

March 22, 2007

Impact!

Piecing together the story of a giant meteorite crater beneath the Atlantic coast

• Buried under Chesapeake Bay is a very well preserved impact structure 56 miles across and more than 2 miles deep
• Following clues from drill holes and seismic imagery, careful detective work in the 1990's identified this ancient buried crater
• When a meteorite 2 miles in diameter slammed into what was then ocean, it instantly blew out a crater 7 miles deep, splashed water and debris 30 miles up, and spawned tsunamis thousands of feet high
• Long-mysterious glass stones ("tektites") found in the eastern U.S. and the Caribbean are now recognized as ejecta from the Chesapeake Bay impact
• After 35 million years, the landscape, drainage patterns, and underground water in the Chesapeake Bay area are still affected by the impact event

April 26, 2007

Shock Waves

How the 1906 earthquake shook up California and science

• The 46-minute film Shock Waves includes dramatic historical footage, colorful animations, and interviews with earthquake experts
• Shock Waves received recognition as an outstanding documentary at the 2006 Telly Awards and has been nominated for an Emmy
• The catastrophe of the great 1906 quake spurred a century of progress in earthquake science and engineering
• Current and future research includes drilling through the San Andreas Fault at depth in the SAFOD Experiment
• Learn what can you do to reduce the risk to yourself and your family

May 31, 2007

Alchemy in the Abyss

Probing the mysteries of deep-ocean minerals

• Since President Reagan in 1983 extended U.S. mineral rights 200 nautical miles offshore, interest in deep-sea mining has increased
• Massive sulfide deposits form rapidly at very hot ephemeral vents..black smokers. and .white smokers.
• Slow-forming manganese nodules cover vast areas of the cold abyssal depths
• Cobalt-rich crusts form extremely slowly on the tops of extinct sunken volcanoes
• The year 2009 may see the first commercial mining of deep-sea polymetallic sulfides in Papua-New Guinea waters

Jun 28, 2007

Adventures in Southwest Geology

Exploring the colorful southern Colorado Plateau in 3-D

• A plethora of parklands- Petrified Forest, Chaco Canyon, Wupatki, Grand Canyon
• High desert climate changes, past, present, and future
• Colorado River history: a river ran through it, but where?
• Desert life and death-- and dunes
• Earth history laid bare: volcanoes, mountain-building, erosion

July 26, 2007

Plate Tectonics in Action

Exploring the Earth with the new edition of This Dynamic Planet map and Web site

• Improved digital data on the distribution of Earth's volcanoes, earthquakes, and meteorite impact craters
• Special maps of polar regions, showing topography beneath the ice sheets
• Informative articles, tables, and illustration on the back of the map
• A series of global images showing the "dance of the continents" through geologic time
• A companion Web site offering an interactive version of the map http://www.minerals.si.edu/tdpmap/

August 30, 2007

Dark Holes in Muir's "Range of Light"

Insights from southern Sierra Nevada caves and karst

• Water long ago carved many caves in carbonate rocks of the Sierra Nevada
• As the Sierra (John Muir's "Range of Light") was uplifted, successively deeper caves were drained and decorated during the past 5 million years
• Vertical arrays of caves document the progressive uplift and erosion in Kings Canyon
• Lilburn Cave, with 21 miles of passages, is California's longest
• New spectacular and pristine caves are still being discovered as recently as 2006

September 27, 2007

A Tale of Two Kelp Forests

Sea Otters and Ecosystem Dynamics in the Aleutians and the Commander Islands

Sea otter populations in the central and western Aleutian Islands have declined by 75-95% over the past 15-20 years, while populations in the nearby Russian Commander Islands have remained roughly stable. There are no obvious environmental explanations for these disparate patterns, as the archipelagos are physically and biologically quite similar. Because of the differing population trajectories and the role of sea otters as keystone predators, the two kelp forest ecosystems that were once very similar are now quite different. What has caused these differences?

October 25, 2007

Fire As An Ecosystem Process

Past, Present, And Future

• Plants have evolved over hundreds of millions of years with fire.
• Are human-induced changes threatening naturally fire-prone ecosystems?
• How has human suppression of fire affected different ecosystems?
• Will predicted climate changes affect future fire-management decisions?

November 15, 2007

Disasters, Dust, .... and Danger?

Using geoscience to help understand whether health risks lurk in particles produced by disasters

• Valley Fever outbreak following the 1994 Northridge, California earthquake
• World Trace Center collapse
• Hurricane Katrina flooding
• 1996 Marinduque, Philippines, mine tailings spill

December 13, 2007

Exploring Antarctica's Frozen Frontier

The USGS Antarctic Program from the 1957 International
Geophysical Year to the 2007 International Polar Year

• Learn about USGS surveying and mapping of "The Frozen Continent"
• Discover how geophysical surveys reveal what lies beneath the ice
• Hear how the United States officially names Antarctic geographic features
• Why does the geographic South Pole survey maker need repositioning?
• See the new high resolution Landsat Satellite Image Map of Antarctica