San Fransisco on EARTH Magazine

Benchmarks: January 3–5, 1982: 18,000 landslides wreak havoc on the San Francisco Bay area

Wed, 06 Jul 2016 10:16:25 -0400

A debris flow blocked a creek in Santa Cruz County. As the water and mud were diverted, a creek bank collapsed, dropping a house into the creek. Credit: California Geological Survey.

The debris flows in some regions were so fast and massive that they transported homes dozens of meters. Credit: California Geological Survey.

When a storm battered California’s San Francisco Bay Area in early January 1982, the rain was intense, but not without precedent. The region had historically endured heavy rains during the winter months, with individual storms sometimes bringing more than half the annual average rainfall in a single 36-hour span. But a collection of unique factors in 1982 created a recipe for a landslide disaster. First, two weather fronts merged, bringing copious amounts of rain to an already saturated region. Second, the rising population had resulted in a construction boom in the iconic hills of the Bay Area. During three days of relentless rain from Jan. 3–5, 1982, a record 18,000 individual landslides occurred, killing at least 25 people.

The most dangerous fault in America

Mon, 09 May 2016 14:35:54 -0400

The entire length of the Hayward Fault runs through densely populated cities such as Oakland, Fremont and Berkeley (shown here), and is not far from the metropolises of San Francisco (background) and San Jose. The U.S. Geological Survey describes the Hayward Fault as "the single most urbanized earthquake fault in the United States." Credit: ©iStockphoto.com/ConstantGardner.

Last summer, a startling article appeared in The New Yorker magazine outlining what could happen to the Pacific Northwest in the event of a large earthquake resulting from a full rupture of the Cascadia Subduction Zone. As recently as 1700, this convergent zone produced an earthquake estimated at magnitude 9. If such an event happened today, the results would be devastating. The article attracted a great deal of attention, especially among people who had never heard of the possibility that the heavily populated Pacific Northwest could, in a geologic moment, become “toast” — as someone quoted in the article put it.

Golden Gate ghost ships rediscovered

Tue, 09 Dec 2014 11:56:13 -0500

A new remote sensing survey of the seafloor off the coast of San Francisco revealed the 1863 wreck of the clipper ship Noonday as well as others. Credit: both: NOAA.

Just beyond San Francisco’s Golden Gate Bridge is a shipwreck graveyard where as many as 300 vessels lie in silty underwater repose. A team of NOAA researchers conducting a two-year study to identify and map the long-forgotten ships in the Gulf of the Farallones National Marine Sanctuary and the adjacent Golden Gate National Recreation Area has announced the discovery of three wrecks: the 1863 wreck of the clipper ship Noonday, the 1910 shipwreck SS Selja and an unidentified early steam tugboat wreck tagged the “mystery wreck” — all now obscured by mud and silt on the ocean floor.