Featured Research

from universities, journals, and other organizations

Tsunami Hunters Probe Lake Bottoms For Clues

Date:
March 6, 1998
Source:
Simon Fraser University
Summary:
When the predicted big earthquake hits off the coast of southwestern British Columbia, communities near sea level will have one more potentially life-threatening hazard to worry about -- tsunamis, or tidal waves.

When the predicted big earthquake hits off the coast of southwestern British Columbia, communities near sea level will have one more potentially life-threatening hazard to worry about -- tsunamis, or tidal waves.

Exactly how big the tsunamis will be and how far inland they will reach depends on the intensity of the earthquake. Still, the best way to predict what might happen is to look back and see what's already happened.

That's why a group of scientists, including SFU geographer Ian Hutchinson and plant paleontologist Rolf Mathewes, have spent the last three years probing the gooey depths of several tiny lakes on the west coast of Vancouver Island.

Preliminary results of their study suggest that tsunamis on Canada's exposed west coast may be smaller than previously thought.

Tsunamis can occur when an earthquake causes the ocean floor to rise or sink, displacing water and creating a series of large waves. The major seismic threat off Canada’s west coast lies 100 kilometres off Vancouver Island at the junction of two huge crustal plates, one of which is sliding under the other. At present, the two plates are locked, but when that lock breaks, the much-heralded large quake will take place.

"When that happens, it will take about 15 minutes, at most, for a tsunami to reach the Vancouver Island coastline," says Hutchinson. "The geophycists tell us that, on the outer coast, the worst waves would be about five metres high. But they'll build as they move up the inlets, meaning that low-lying communities such as Port Alberni could be hit by waves as high as 15 metres. That's a significant hazard."

Funded by the U.S. Geological Survey, Hutchinson and colleagues set out to find field evidence of past tsunamis in the region. "Other researchers are working on computer models of what these earthquake events might look like all along the Pacific coast," says Hutchinson. "It's important that they get real evidence of tsunamis in this region."

The team used a 'corer' -- basically a hollow tube -- to bore three metres into the sediments of small coastal lakes less than five metres above sea level. Core samples were examined for debris that might have been deposited by a big wave, and plant material was used to date each layer. "In one lake we got a record going back 3,000 years," Hutchinson says. "Some of them can go even longer if we could get deep enough."

Of the eight lakes cored to date, three have yielded tsunami deposits. "The lake bottoms are like brown gelatin, rich in organic matter," explains Hutchinson. "But tsunami deposits consist of gravels, sands and lots of forest material, because when a tsunami wave rushes into a lake, it strips the forest floor."

The team hopes to take more lake samples this summer, with a longer coring system that can go deeper -- and further back in time. So far, the results suggest that west coast tsunamis may not be as severe as widely believed.

"Some of the earthquakes that we thought would generate tsunamis don't appear in the core record," says Hutchinson. "It may be that most tsunamis produced offshore only reach up to three metres in height on the outer coast."

That would be good news for communities nestled in inlets, he adds. "A smaller wave might make all the difference in terms of whether there's widespread devastation or not."


Story Source:

The above story is based on materials provided by Simon Fraser University. Note: Materials may be edited for content and length.


Cite This Page:

Simon Fraser University. "Tsunami Hunters Probe Lake Bottoms For Clues." ScienceDaily. ScienceDaily, 6 March 1998. <www.sciencedaily.com/releases/1998/03/980306043321.htm>.
Simon Fraser University. (1998, March 6). Tsunami Hunters Probe Lake Bottoms For Clues. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/1998/03/980306043321.htm
Simon Fraser University. "Tsunami Hunters Probe Lake Bottoms For Clues." ScienceDaily. www.sciencedaily.com/releases/1998/03/980306043321.htm (accessed July 29, 2014).

Share This




More Earth & Climate News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins