Geologist will tell moving story of rocks, glaciers and fault lines

To the untrained eye, the Wrangell landscape looks serene and still, with its craggy, tree-covered hills, gray pebble beaches and sweeping ocean views.

But to federal geologist Peter Haeussler, the land is full of hidden forces, operating on a timetable much vaster than our own. The color of a rock or the shape of a valley offer clues that can unlock the secrets of an area's past - and point to its future.

Haeussler will share his expertise on Southeast geology at 2:30 p.m. Saturday at the Nolan Center.

"I think one of the fun parts of being a geologist is that you're basically a detective," he said. "You show up at the scene of a crime ... and you try to figure out what it was that actually happened. And you have various tools to try to figure it out. But it's also not like a chemistry experiment in that you can repeat it. Earth history only happened once."

For example, the "ugly gray rocks" around Wrangell are a variety that only form in deep ocean basins. "Those rocks are telling me a story that there was an ocean that is now closed. That ocean is gone."

And though the great-great-grandmothers of today's Evergreen Elementary students may have played on the same rocks and looked out at the same views when they were children, the Southeast Alaska area is actually changing at a breakneck speed, when viewed at the scale of geologic time.

Fast-moving faults - or fractures between two rocks - typically slide at a whopping one centimeter per year. The Hollywood-famous San Andreas fault in California moves at around 3 centimeters per year. The Queen Charlotte fault, which runs the length of Southeast and into British Columbia, is moving at five centimeters per year, making it the fastest moving fault system of its kind in the world.

Geological change may happen too slowly to be detected by the naked eye, but these imperceptible shifts can have significant consequences for communities, since seismic and volcanic activity often occurs around fault zones.

Haeussler works for the U.S. Geological Survey, where he maps the sea floor and collects rock samples. His findings are used to help keep people safe.

"A lot of the work ends up going into seismic hazard maps for the nation," he explained. "There's about a trillion dollars of new construction per year in the U.S. And so essentially it goes into building codes, which then hopefully makes for safer places to live and work."

Since he was young, Haeussler has been passionate about the natural sciences, but didn't know he wanted to be a geologist until he started exploring the Rocky and Teton mountain ranges. "That is the kind of terrain that drew me in," he recalled. "I also got into rock climbing, and at some point I started to wonder what it was that I was climbing on. And you start asking questions about the landscape and how did it get here."

His upcoming talk will appeal to anyone who has asked similar questions about the contours of the region. He plans to touch on plate tectonics, glacial pathways and more.

Before the glaciers that used to sit atop Southeast moved out to the ocean, their weight depressed the land underneath them. Then, as the glaciers shifted west, the weight was lifted and the land sprang back up.

"There's this up and down history of glacial movement that affects what's at the shoreline," he said. "The paleo shorelines ... are much higher here in Southeast Alaska."

Sylvia Ettefagh, co-owner of Alaska Vistas tour company, invited Haeussler to speak after she noted the community's interest in geology. The event is sponsored by Alaska Bearfest, which is scheduled for the last week of July in Wrangell.

"Geology, especially seismology, seems to be something a lot of people are looking at," she said, citing Wrangell High School's Shake Club, which has been tracking seismic activity on the island since last fall. "Peter has a boat that he keeps in Wrangell, so the timing just worked out."

Residents have told Ettefagh that they're curious about the landscapes they inhabit - how they were formed, why they look the way they do, what the future might hold. "I've gotten a lot of feedback from sending feelers around the community that people are excited," she said.

Haeussler anticipates giving a roughly 45-minute lecture followed by a question and answer period. Ettefagh encourages attendees to "come loaded with questions."

"I expect that beyond the presentation, the questions and answer opportunity is probably going to be pretty cool," she said.