May 16, 2013 10:11 am
In 1700, a massive earthquake struck the west and northwest coast of the United Sates. Modern scientists first caught wind of the natural disaster through the scars it left on the land—massive, toppled red cedar trees and sand deposits washed far inland. Written records weren’t being kept in that region when the earthquake happened, but several years ago, scientists managed to pinpoint the date of that mysterious earthquake. In 2005, Smithsonian explained how they unraveled the mystery:
In Japan, officials had recorded an “orphan” tsunami—unconnected with any felt earthquake— with waves up to ten feet high along 600 miles of the Honshu coast at midnight, January 27, 1700. Several years ago, Japanese researchers, by estimating the tsunami’s speed, path and other properties, concluded that it was triggered by a magnitude 9 earthquake that warped the seafloor off the Washington coast at 9 p.m. Pacific Standard Time on January 26, 1700. To confirm it, U.S. researchers found a few old trees of known age that had survived the earthquake and compared their tree rings with the rings of the ghost forest cedars. The trees had indeed died just before the growing season of 1700.
The earthquake occurred along the Cascadia Subduction Zone, a major fault line running from the Pacific Northwest to Vancouver. In recent decades, scientists have determined that this fault line may produce mega-earthquakes of 9.0 or higher on the Richter scale.
Considering all the geologic evidence, scientists now say a major earthquake strikes the Pacific Northwest every few hundred years—give or take a few hundred years. That means the next one could strike tomorrow.
This is why researchers hope to learn as much as they can, as quickly as they can about the devastating quake that rocked the land back in 1700. Earthquake prediction remains notoriously sketchy (just look at the recent example of researchers in Italy who failed to predict an earthquake in L’Aquila), so the more scientists can learn about what happened in the past, the better prepared they can be for the next disaster. And that next one could be coming soon, according to new research:
The Cascadia subduction zone is of particular interest to geologists and coastal managers because geological evidence points to recurring seismic activity along the fault line, with intervals between 300 and 500 years. With the last major event occurring in 1700, another earthquake could be on the horizon. A better understanding of how such an event might unfold has the potential to save lives.
The University of Pennsylvania team turned to a fossil-based technique for studying the Cascadia Subduction Zone. They took core samples throughout the region and then picked through the samples to find microscopic foraminifera fossils, a type of single-celled aquatic protist. They used radiocarbon dating to estimate the age of these ancient creatures and to recreate past changes in land and sea level along the coastline. Through their analyses, they saw that the coastline ruptured in a heterogenous manner, or that the earthquake struck in different locations with different severity.
The earthquakes that occurred in this part of North America, they report, behaved similarly to recent major earthquakes in Japan and Chile, which arrived with very little warning. While the results are useful for modeling and understanding the next West Coast mega-earthquake, the researchers warn that some areas in Oregon will likely have just 20 minutes to evacuate before the tsunami waves arrive.
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May 14, 2013 3:19 pm
Last year was one of the worst wildfire seasons in Colorado’s recent history. A series of destructive blazes drove tends of thousands of people from their homes and caused hundreds of millions of dollars of damage.
Last year’s awful fire season was spurred by a dry winter and higher-than-average temperatures. Those same conditions are back, says Climate Central, and the western U.S. is at risk once more.
Drought conditions have encompassed nearly the entire Western half of the country, with the worst of it centered in the Southwest and into California, which received only about 25 percent of its average precipitation during the year-to-date. “We’re confident we’re going to see above-normal significant fire potential,” Sullens said.
From California to Colorado, he says, the early-summer fire risk is high. Indeed, California has already seen a big blaze.
Forecasters are also concerned about a high risk of large wildfires along the Pacific Coast from California northward to Washington, and inland into Idaho and Southwest Montana, where very dry conditions exist in areas that have an abundance of vegetation, or fuel, to support potential fires.
… Vilsack said the combination of the drought, an abundance of dead or weakened trees from an epidemic of mountain bark beetles, and a likelihood of another unusually hot and dry summer is “a combination that doesn’t bode well.”
In many places the spring fire season has been off to a slow start, says Andrew Freedman, but according to the federal government this “has no bearing on where we think this fire season is going to go.”
More from Smithsonian.com:
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Australia is Burning, And It’s Only Going to Get Worse as the World Warms
Devastating Colorado Wildfires Most Recent in Decades-Long Surge
Fires Are Escaping Our Ability to Predict Their Behavior
May 13, 2013 12:49 pm
In 1066, the town of Dunwich began its march into the sea. After storms swept the farmland out for twenty years, the houses and buildings went in 1328. By 1570, nearly a quarter of the town had been swallowed, and in 1919 the All Saints church disappeared over the cliff. Dunwich is often called Britain’s Atlantis, a medieval town accessible only to divers, sitting quietly at the bottom of the ocean off the British Coast.
Now, researchers have created a 3D visualization of Dunwich using acoustic imaging. David Sear, a professor at the University of Southampton, where the work was done, described the process:
Visibility under the water at Dunwich is very poor due to the muddy water. This has limited the exploration of the site. We have now dived on the site using high resolution DIDSON ™ acoustic imaging to examine the ruins on the seabed – a first use of this technology for non-wreck marine archaeology.
DIDSON technology is rather like shining a torch onto the seabed, only using sound instead of light. The data produced helps us to not only see the ruins, but also understand more about how they interact with the tidal currents and sea bed.
Using this technology gives them a good picture of what the town actually looks like. Ars Technica writes:
We can now see where the local churches stood, and crumbling walls pinpoint the ancient town’s remits. A one kilometer (0.6 mile) square stronghold stood in the center of the 1.8km2space (about 0.7 square miles), with what looks like the remains of Blackfriars Friary, three churches, and the Chapel of St Katherine standing within it. The northern region looks like the commercial hub with lots of smaller buildings largely made of wood. It’s thought that the stronghold, as well as its buildings and a possible town hall, may date back to Saxon times.
Professor Sears sees this project as not just one of historical and archaeological importance, but also as a forecast of the fate of seaside cities. “It is a sobering example of the relentless force of nature on our island coastline. It starkly demonstrates how rapidly the coast can change, even when protected by its inhabitants. Global climate change has made coastal erosion a topical issue in the 21st Century, but Dunwich demonstrates that it has happened before. The severe storms of the 13th and 14th Centuries coincided with a period of climate change, turning the warmer medieval climatic optimum into what we call the Little Ice Age.”
So, in a million years, when aliens come to look at our planet, it might look a lot like Dunwich.
More from Smithsonian.com:
May 6, 2013 1:20 pm
For two years the majority of the continental U.S. has been plagued by drought, a confluence of natural cycles that have worked together to drive up temperatures and dry up the land. But for all the damage that has been done by the long-running drought, there’s been an upside as well. The lack of water in the atmosphere has also sent the U.S. toward a record low for tornadoes, says Climate Central‘s Andrew Freedman.
The National Severe Storms Laboratory (NSSL) in Norman, Okla., estimates that, between May 2012 and April 2013, there were just 197 tornadoes ranked EF-1 or stronger on the Enhanced Fujita scale. That beats the previous 12-month low, which was 247 tornadoes from June 1991 and May 1992.
That’s the lowest recorded tornado activity since 1954, when scientists first really started keeping track. The number of deaths connected to tornadoes went down, too:
The U.S. did set a record for the longest streak of days without a tornado-related fatality — at 220 days — between June 24, 2012 and Jan. 26, 2013. And July 2012, which was the hottest month on record in the U.S., saw the fewest tornadoes on record for any July.
But the tornadoes didn’t just up and disappear, says Freedman in an August story. Rather, some of them just moved to Canada.
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May 2, 2013 9:30 am
Many parts of New York City are still reeling after Superstorm Sandy. Residents of the Rockaways are still without homes, and Breezy Point residents trying to rebuild their community are fighting with insurance companies and contractors. A recent report by Climate Central uncovered a few other unsavory side effects of the storm as well. Like the 11 billion gallons of sewage that ran from treatment plants into waterways during the storm.
This Bloomberg story puts that number into context. “That total is equal to New York’s Central Park stacked 41 feet high with sewage,” it says. The report found that of that sewage was partially treated, but about a third of it was totally untreated raw sewage. And 94 percent of the it spilled out due to the damage caused by coastal flooding. The problem hasn’t gone away either. Climate Central writes that “the last known Sandy-related sewage overflow took place in January 2013.”
Sewage treatment facilities are particular vulnerable to storm surges: they’re often built in low-lying regions and near water so that the sewage they treat can be released easily. Which means that future climate change and sea level rise will put these treatment plants at immediate risk. Climate Central’s press release:
“Sandy showed the extreme vulnerability of the region’s sewage treatment plants to rising seas and intense coastal storms,” said Alyson Kenward, lead author of the report. Most experts expect seas to rise between 2 to 4 feet by the end of the century even if aggressive actions are taken to control emissions of greenhouse gases.
Fixing the damage that Sandy caused will be expensive. State authorities say that in New York alone they’ll need to spend $2 billion. New Jersey has set aside $1 billion for repairs, and $1.7 billion for building a more resilient system to prevent future sewage outflows.
Climate Central built an interactive graphic to explain just where the sewage came from and went:
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