The Bay Area encompasses an extensive network of fault fractures. The Hayward fault, running parallel to the more famous San Andreas Fault, has shifted only slightly since 1868. Computer simulations help scientists test possible scenarios, to see the impact of a Hayward Fault quake on the Bay Area. Information such as the proximity of mountains, type of soil, and other factors are used to calculate shaking intensity. This information allows engineers to design safer structures for earthquake prone areas.
Looking back through geological time to a point 200 million years in the past, the continents looked very different from today. India and Antarctica were neighbors. Buenos Aires and Cape Town were much closer than they are today. And Morocco and New York City were separated by a thin strait, which eventually expanded into the Atlantic Ocean. The formation of the Atlantic occurred as new crust formed along the underwater Mid-Atlantic ridge, driving the breakup of Pangaea. By speeding up geologic time, we can witness the movement of the plates and the break up of larger landmasses into the continents we recognize today.
Sometimes geologic time, human time, and historical time intersect. Jumping back in time to 1906, we see an accurate representation of the city of San Francisco at the turn of the century. We view the Ferry Building in the early morning of April 18, 1906, traveling up Market Street to witness approximately 20 seconds of the 1906 Earthquake (which actually lasted about 90 seconds). In the aftermath of the earthquake, fires erupted and destroyed 500 city blocks—30,000 buildings. Approximately 3,000 people died in the 1906 earthquake and fire. The tragedy motivated Californians to study earthquakes in greater detail, giving birth to modern earthquake science.
Seismic waves help scientists decipher Earth’s interior structure. The layers of the inner Earth include the thin crust, the rocky mantle, and superheated metal core. The heating and cooling of the mantle drives the constant movement of tectonic plates. These plates float atop the denser mantle and interact with one another. Some plates spread apart allowing the formation of new crust, some move towards each other, and others, like the plates in California, grind against each other moving side by side in opposite directions. These movements continue to transform the surface of Earth.
Engineers use computational models to simulate shaking of building materials, and real-world tests are conducted on large shake tables using accurate seismic data. Engineering designs, including the isolation bearings found below a structure, enable engineers to strengthen buildings such as San Francisco’s City Hall. The iconic Ferry Building survived the 1906 earthquake, and it too has benefited from engineering improvements to prevent damage during future quakes.
We can plan for a safer tomorrow, not only by designing more resilient buildings, bridges, and other infrastructure, but also by making decisions about preparedness in our daily lives. Although we do not know when the next earthquake will occur, we do know that human time and geological time will eventually intersect once again.
Earthquakes have affected our human ancestors since the time the early hominins evolved along the East African Rift, in a region shaped by plate tectonics. Early civilizations may have settled in tectonically active areas for the benefits accrued in the shadows of mountain ranges and volcanically-enriched soils. The island of Cyprus offers another example: oceanic crust lifted to the surface by tectonic activity exposed veins of copper that provided raw materials during the Bronze Age.
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Creative design and boundary-breaking technology helped make ORACLE TEAM USA the world’s fastest sailboat in the 2010 America’s Cup World Series. Catch a glimpse of the winning AC45 catamaran, suspended from the ceiling between the Swamp and the Piazza through September 2013.
One of the oldest fossils ever discovered dated at 3.2 million years old, "Lucy" (Australopithecus afarensis) provided scientists evidence of bipedal, upright walking by human ancestors. In this animation, see what similarities Lucy shares with modern humans.
Trace the milestones of our species’ fascinating history in a dramatic addition to Tusher African Hall.
For more information visit http://www.calacademy.org/human-odyssey/
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Astronomer Jill Tarter chats about some of the interesting things she has done in her career, dealing with the scientific question "Are we alone in the Universe?" Jill has recently stepped down from her long held position as director at the SETI Institute (Search for Extraterrestrial Intelligence)