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Geology on the Edge planned itinerary July 11-19 2015 (please understand that all best laid plans are subject to change)

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 1. The Hayward fault in Berkeley and Hayward

Driving: 45 mi./ 1 hr. Instruction: 3 hr. Map. KMZ, Photos1 and 2

Our 9:25 AM flight from ATL should put us in San Jose before noon. We will follow the Hayward fault, the fault in the Bay area with the highest probability of a major quake, to UC Berkeley, with its stadium astride the Hayward fault. It is the most recent of many buildings we will see on campus to be redesigned and rebuilt for improved earthquake readiness. Returning to Hayward for the night, we will see cracked buildings and sidewalks, and a neighborhood built atop a pressure ridge, all evidence of ongoing movement.

Questions: How are the faults recognized? How have they shifted the landscape on various time scales? Why are both pull-apart and compressional features found along these faults? What damage have the faults done to buildings? How is risk determined and responded to?

Day 2. Gold Rush Country: Castro Valley to Mariposa

Driving: 170 mi./ 3.4 hr. Instruction: 5 hr. Map, KMZ, Photos

Cross California's Central Valley, learning factors that made it one the world's most productive farming areas. Visit the preserved gold rush town of Columbia, see rocks that tell the geologic story behind California's gold deposits, and visit the California State Mining and Mineral Museum in Mariposa.

Questions: Why was the gold concentrated along a linear belt? How did the uplift of the Sierra Nevada influence Central Valley and the gold deposits? What impacts did the gold rush have on the landscape and on American history?

Day 3. Yosemite National Park: Mariposa to Mammoth Lakes

Driving: 194 mi./ 5.2 hr. Instruction: 3 hr. Map. KMZ, Photos 1 & 2, 3, and 4

Begin at Yosemite Park's Glacier Point for a view of the valley and Half Dome, then visit the foot of Yosemite Falls. Continue into the high country where the ice sheet originated, observing the debris and erosional trail that the ice left behind. Leaving the park, descend the steep side of the Sierra Nevada to the rain shadow desert, then continue to Mammoth Lakes where a break in the Mountains interrupts the rain shadow.

Questions: Can a pre-glacial history be read in this landscape? Why was Whitney so sure Muir was wrong about the glacial origin? How are the intrusive igneous rocks here similar to and different from Stone Mountain, GA? What evidence have the glaciers left of their passage?

Day 4: North from Mammoth Lakes (AM); Gondola on Mammoth Mountain (PM)

Driving: 86 mi./ 2.6 hr. Instruction: 6 hr. Map. KMZ, Photos 1 and 2

Make a short ascent of Panum Crater, a volcano built of obsidian and pumice that last erupted 700 years ago. Nearby, examine tufa (calcite) towers formed by evaporation of Mono Lake's waters. Signs describe the court decision forcing Los Angeles to slow its diversion of waters feeding the lake to a renewable speed, saving the lake. On the return leg, observe how a fault scarp interacted with glaciation to produce a horseshoe-shaped drainage as we pass LA's reservoir, Grant Lake, and Silver Lake. Then visit the base of Obsidian Dome, formed when viscous magma oozed from a vent about 600 years ago.

After lunch, we take a gondola ride up Mammoth Mountain, a favored ski resort because of a break in the Sierra Nevada that lets Pacific moisture in as snow. It is also a volcano that last exploded about 50,000 years ago. The gondola ride up the mountain passes a vent that smells of sulfur, which killed three ski patrol staff in 2006 with dangerous levels of carbon dioxide gas.

Questions: Why is there both obsidian and pumice at Panum Crater, but only obsidian at Obsidian Dome? How does tufa form and why are the towers hollow? Is it a coincidence that some of the youngest volcanoes are at Mono Lake? How did the locals prevail in saving the lake against the powerful city? Could Mammoth Mountain erupt without much warning?

Itinerary Day 5: West from Mammoth Lakes

Driving: 39 mi./ 2.0 hr. Instruction: 6 hr. Map, KMZ, Photos

Devil's Postpile National Monument is a classic location to see hexagonal columns of basalt up to 60 feet high. Minaret Summit en route offers panoramic views. On the return we stop at the misnamed "Earthquake Fault," a puzzling gash in the Earth. After lunch we venture out to Horseshoe Lake, at the foot of Mammoth Mountain, where volcanic CO2 has killed all the vegetation, and take a short hike to the beautiful alpine McLeod Lake.

Questions: Why does cooling magma break into neat hexagonal columns? Why would a gash in the ground remain unfilled by debris? Why do some volcanoes emit CO2? Is it enough to put signs in the area warning hikers and skiers, or should it be off-limits?

Itinerary Day 6: South from Mammoth Lakes

Driving: 117 mi./ 3.1 hr. Instruction: 6 hr. Map. KMZ, Photos 1 and 2

Long Valley Caldera, (with Yellowstone) one of two active supervolcanoes in the contiguous 48 states, is related to a new pull-apart plate boundary. We look at layers of the huge ash deposit expelled by the eruption 760,000 years ago, see a gorge carved in that deposit by the Owens River, visit Hot Creek at which earthquake episodes released scalding waters, and climb an active fault scarp that cuts a young glacial deposit.

Questions: If Long Valley Caldera had a similar eruption today, what would the human consequences be? Have eruptions of this scale happened in historical time? Why were the hot springs closed to bathers? Does the hot water have economic value? Is there a relationship between the faulting and the hot springs?

Itinerary Day 7: Mammoth Lakes to San Rafael via John Muir National Historic Site

Driving: 285 mi./ 6 hr. Instruction: 2 hr. Map. KMZ

Our longest travel day will be dedicated to the man who founded the Sierra Club and was the first to decipher the glacial origin of Yosemite Valley. En route across the Sierra and Great Valley, there will be an opportunity to hear recordings by actor Lee Stetson of some of John Muir's incredible stories, such as a night surviving a blizzard on Mt. Shasta, by huddling in a volcanic fumarole. Our one field stop will be at Muir's home in Martinez, California.

Questions: Does Muir deserve to be remembered as the "Father of our national parks"? Could he really have ridden an avalanche with little injury, as he claimed?

Itinerary Day 8: Colorful rocks from Angel Island to Devil's Slide

Driving: 92 mi./ 2.6 hr. Instruction: 5 hr. Map. KMZ, Photos

A short ferry ride takes us to car-free Angel Island, for an optional hike to see unusual subduction-zone rocks (blueschists). Returning to land, we drive to Rodeo Beach for red deep-sea chert resting on some of the best preserved pillow lavas on land. Then we cross the Golden Gate Bridge and the San Andreas fault to spectacular Devil's Slide, until recently a dangerous stretch of CA 1. Now bypassed by a tunnel, the walking trail reveals granite similar to Yosemite's, possibly shifted here from near the southern end of the Sierra Nevada. The last stop of the day is San Andreas Lake, nestled in a pull-apart valley made by the famous fault named after the lake.

Questions: Why is blueschist so rarely seen? What is pillow basalt and why is it often associated with red chert? Is it risky to have dams astride the San Andreas fault, as there are south of natural San Andreas Lake?