Sunday December 8, 2013
Geology gave the world the gift of immense time: not just the measly millennia counted by old civilizations, but millions of years and billions of years, more years than anyone could count. It made even the absurdly long sacred chronologies of the Hindus look reasonable. And as we explored all that time, we figured out how to organize it into structures of time, hierarchies of time periods with, eventually, actual dates assigned to them. That's what this week's "Who Wants to Be a Geo-Whiz?" quiz is about: geologic time. Now don't dawdle, you've only got a week.
Saturday December 7, 2013
This message is for the thousands of geoscientists arriving for the coming week's Fall Meeting of the American Geophysical Union
. If you're going to San Francisco, be sure to wear . . . some decent walking shoes. Because the city is full of geological attractions. I've got a fair sampling of them in this photo-tour
. Some of them might be unexpected; for instance, the Japanese Tea Garden in Golden Gate Park displays some of the different local rock types with plantings and decorations that complement them. There are no signs pointing this out, just little pleasures awaiting your tranquil, enlightened gaze.
San Francisco geology
More California geology
Visit San Francisco
Franciscan basalt Geology Guide photo
Wednesday December 4, 2013
A brief remark at a talk in October led me to a clever bit of science that offered a way through the paleomagnetic mirror problem. By that I mean the ambiguity that results when a moving continent heads toward the equator. The paleomagnetic record shows it reaching the equator, then moving closer to the magnetic polebut in which hemisphere? Just from magnetic evidence, there's no way to decide whether the continent plowed straight onward into the opposite hemisphere or backed off and stayed on its original side of the line. The solution had to do with the Coriolis force, the only way we have to tell the left-handed hemisphere from the right-handed hemisphere. So far this method has been useful only once, but I was pleased that a method existed at all. Details in this new article, "Disambiguating the Paleomagnetic Record."
Tuesday December 3, 2013
The city of Vancouver, British Columbia, in 2011 commissioned an update to its plans to deal with a large earthquake. This is a big deal because Vancouver, like Seattle and Portland and many other cities in the Pacific Northwest and northernmost California, all face the threat of a Japan-style magnitude-9 earthquake at a time unknown. It's also a big deal to me because next year's annual meeting of the Geological Society of America will be in Vancouver. The Canadian news site Global News summarizes the story, and a presentation about the plan (PDF) is online. It has the look of a Powerpoint presentation, but that keeps things simple and digestable.
Regardless of the steps Vancouver plans, it's worth contemplating what the report says about a big quake there. Six big things: (1) damage to buildings and infrastructure, but you knew that; (2) fires start as gas lines break, but maybe you knew that too; (3) the electricity fails; (4/5) 9-1-1 and the phone system are swamped; (6) "people flood to the streets and begin making their way from the areas of major damage." Don't count on taking your well-packed Land Rover anywhere.
Vancouver's report noted that the recent New Zealand earthquake "demonstrated the importance of trained volunter response." And Vancouver has launched a Vancouver Volunteer Corps, now more than 800 strong, to be ready to help by taking part in training and regular exercises. My particular interesthow we rebuild, and who benefitsis not addressed, but that's a fearsome topic and I understand.
Smashed home in Christchurch image from Vancouver report