He’s a scientist with the U.S. Geological Survey whose expertise is studying ancient earthquakes and tsunamis, and he joined us as a guest in this Science Forum discussion.

Atwater digs in the soil for evidence of natural disasters that occurred in the past — to provide clues to the risks we face today.

Atwater says the massive earthquake and tsunami that struck northeastern Japan last week had a precedent.  It occurred in the 9th century.  Based on written records from that time and sand deposits left in the ground, Japanese scientists conclude that on July 13, 869, a tsunami swept more than 4 kilometers inland in the area around the modern-day city of Sendai.

Using similar detective work, Atwater concludes that a massive tsunami struck America’s Pacific Northwest more than 300 years ago.  He and his colleagues found evidence of this tsunami in sediments along the coast of California, Oregon, Washington, and British Columbia.  They believe this is the same tsunami that was recorded striking Japan in January 1700, and that it originated on this side of the Pacific.

Atwater and his colleagues recount their detective work in The Orphan Tsunami of 1700–Japanese Clues to a Parent Earthquake in North America.

Read our conversation with Atwater below:

• Which coasts are threatened by tsunamis?
• What can old documents and sediments tell us about today’s tsunami hazards?

Additional Reading

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This week: The World’s Technology Correspondent Clark Boyd is back, with five stories about environmental change. Climate scientists show that, if it weren’t for greenhouse gases, the Arctic would be getting colder rather than warmer. Senegal struggles to maintain its once bountiful fish stocks. Indonesian communities nurture mangroves. Two scientists check in from research vessels–one in a slurry of swirling garbage, one off the shore of a recovering volcanic island. Plus, neuroscientists follow up on China’s Sichuan earthquake, and geologists expose a fake moon rock.

Elsa’s favorite science stories:

• Earthquake Trauma: Neuroscientists have detected the earliest known signs of psychological trauma in the brain. Researchers examined survivors of China’s 2008 Sichuan earthquake just a few weeks after the disaster. (The study.)

• Fake Moon Rock: Under a geologist’s microscope, a Dutch museum’s prized “moon rock” turns out to be common petrified wood. (Here’s a news story. We got the scientific details from geologist Frank Beunk.)

Arctic Ice: A new study provides the most detailed record yet of past Arctic temperatures–and confirms that recent warming is linked to greenhouse gases. Researchers used lake sediments, ice cores, and tree rings to reconstruct 2,000 years of Arctic temperatures. Only in the 1990′s did the enhanced greenhouse effect reverse a long-term cooling trend caused by a wobble in Earth’s orbit.
Report: By The World’s Katy Clark.

Senegalese Fisheries: In the 1970’s, thousands of Senegalese workers turned from mining and farming to fishing, and large foreign trawlers began to ply the same waters. Decades later, the fish are in trouble. The Senegalese government and local councils are now struggling to cut back on fishing and preserve what’s left of their marine resources.
Report: By Jori Lewis in Senegal. (See photographs here.)

Restoring Mangroves: In the past three decades, Indonesia has cleared more than half its mangroves for charcoal, firewood, and fish or shrimp farms. The destruction of these coastal habitats left the Asian nation more vulnerable to damage from the deadly 2004 tsunami. Now Indonesia is working to restore its mangrove forests.
Report: By Ari Daniel Shapiro in Indonesia. (See photos here.)

Life after Eruption: Alaska’s volcanic island Kasatochi erupted last year, burying the island in a thick layer of ash. It seemed that nothing could survive the scorching onslaught, but researchers have found some surprises as they document the gradual rebirth of Kasatochi’s ecosystem.
Guest: Entomologist Derek Sikes, University of Alaska’s Museum of the North.

Pacific Plastic: Garbage from the west coast of North America and the east coast of Asia ends up swirling in a giant, slow whirlpool known as the North Pacific Gyre. Scientists on a research ship near the gyre are trying to understand how marine organisms—from bacteria to whales—are interacting with the vast slurry of disintegrating plastic.
Guest: Oceanographer Miriam Goldstein, Scripps Institution of Oceanography.

Earthquake trigger?

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This week: Swine flu among the Inuit, typhoons trigger earthquakes, elephants afraid of bees, too many jellyfish, and bigger black holes.

Inuit Flu: The World Health Organization has announced that it’s particularly worried about Inuits in northern Canada. That region is experiencing a cluster of cases.
Guest: CBC reporter Patricia Bell, under swine flu quarantine in the town of Iqaluit, the capital of Nunavut.

Typhoons and Earthquakes: A new study has found that one kind of catastrophe – typhoons – may actually trigger another, earthquakes. But it’s more complicated, because these earthquakes are the “slow” kind, which means no one notices them.
Guest: Geophysicist Alan Linde of the Carnegie Institution in Washington

Science News:
A new scientific paper reviews why jellyfish are taking over the seas. (The study.) And as long as you’re thinking about jellies, you might want to enter or vote in this jellyfish naming contest.

Elephants are afraid of something else that stings: bees. Researchers have taken advantage of this to develop “beehive fences,” which seem to work well. (The study.)

Black holes turn out to be much bigger than we thought. (The study isn’t published yet, but here’s an article from Science News about the work.)

Music:
Earthquake, by Jackie Mittoo.
Stormy Monday Blues, by T-Bone Walker.

All over the world, disease and habitat destruction have caused honey bee numbers to plummet. Bees are crucial because they pollinate 80 percent of our fruit and vegetable crops. This week’s podcast begins with a story from Frankfurt, Germany, about how urban apiculture may give the bees a boost.

A bigger environmental problem is climate change. Everyone thinks of cars as a key contributor to global warming, but buildings are responsible for about half the total greenhouse gas emissions and energy consumption around the world. One group of architects wants to change that. They call themselves Architecture 2030. By 2030, they want to design buildings that use no fossil fuels.

Last week, an earthquake hit central Italy, killing almost 300 people. One Italian scientist, Giampaolo Giuliani, a researcher at the National Physical Laboratory of Gran Sasso, predicted the earthquake on the basis of increased radon levels. Nano Seeber, a seismologist at the Lamont-Doherty Earth Observatory at Columbia University, talks about the difficulties in predicting earthquakes. Keep an eye on other earthquakes around the world at the USGS Earthquake Center.

Also this week: chimpanzees exchange meat for sex; some birds can tell where you’re looking; and researchers propose a clever new way to stop malaria by killing only old mosquitoes (see the original research paper).

Music:
Slim Harpo, I’m a King Bee
The Hives, A Stroll Through Hive Manor Corridors