Landslides

landslides

Benchmarks: November 18, 1929: Turbidity currents snap trans-Atlantic cables

On the evening of Monday, Nov. 18, 1929, a magnitude-7.2 earthquake ruptured off the coast of Newfoundland, Canada. Those living on the Burin Peninsula, a foot of land that reaches into the Atlantic Ocean, reportedly felt five minutes of shaking — a confusing sensation, since no one in the area had experienced an earthquake before. “Suddenly this roar — this loud banging — [occurred] and the kettle and the plates started to dance,” Gus Etchegary, a resident of the Burin Peninsula who had experienced the quake, described in a documentary video produced by The Newfoundland and Labrador Heritage Website.

18 Nov 2017

Can distant earthquakes trigger submarine landslides?

Large earthquakes can nudge both nearby and distant faults closer to failure, sometimes setting off additional earthquakes halfway around the world. New evidence from the Cascadia Subduction Zone suggests that large seismic events can also trigger submarine landslides, called turbidity currents, perhaps as far as 13,500 kilometers away. If true, researchers say such long-distance connections could complicate interpretations of paleoseismic records from the Cascadia margin and elsewhere that rely on data from turbidites — the stratified remains of the underwater slides — to piece together when past local earthquakes occurred. But not everyone is convinced that long-distance landslide triggering is possible.

23 Oct 2017

Fungi stabilize steep slopes

The steep slopes of Switzerland’s high Alps are unstable — with loose soil and few plants — which poses hazards such as shallow landslides. In a new study, researchers have found that the symbiosis between plant roots and mycorrhizal fungi helps ground gravelly hillsides, suggesting a possible eco-engineering tool to stabilize the slopes.

30 Jan 2017

Slow-moving slides may be triggered by cold temperatures

Landslides aren’t always fast-moving disasters. Slow landslides creep downhill at rates up to a few meters a year, which might not sound dramatic, but slow slides can still damage roads, pipelines and communities. Slow-moving slides are most commonly triggered by increased pore pressure in the soils due to rainfall or snowmelt, but in some places, according to a new study, temperature may also play a role. The new study looking at slow slides in Japan found that cold underground temperatures — independent of increased rainfall — may lubricate slow-moving slides.

27 Dec 2016

A story in the sediment: Emperor Yu's "Great Flood" may have been real

Ancient Chinese texts re-count the story of a great flood on the Yellow River some 4,000 years ago and Emperor Yu’s heroic efforts to dredge and redirect floodwaters, thereby taming the prolonged and catastrophic floodwaters and setting the stage for the agricultural boom that followed. His success is said to have proved a divine mandate for establishing the Xia dynasty, the first in China’s history. But in the absence of geological evidence for such a flood, scholars have long disagreed as to the veracity of the story.

13 Dec 2016

Ancient landslide gave us Zion Canyon

It took about 20 seconds for the Sentinel rock landslide to tumble into Zion Canyon, but those seconds changed the landscape for thousands of years.

 
03 Oct 2016

California drought stops slow-moving landslides

Most people think of landslides as fast-moving events, but many slides creep slowly, advancing over hundreds or thousands of years. In a new study, researchers looking at creeping landslides in California have revealed an unexpected consequence of the state’s ongoing drought: Many of the slides have nearly stopped due to the lack of water in the soil.

27 Sep 2016

Vibrations make large rocky landslides flow like water

There is a rule of thumb in geology for how far a landslide will run out: Most landslides travel roughly twice the vertical fall distance from where they fall off their parent slope. But certain types of dry landslides, called sturzstroms, can travel 20 to 30 times farther, without water or mud to lubricate the flow. Scientists have long hypothesized about exactly how this occurs, and new computer models seem to back up their hypotheses: that vibrations generated by dry rocky landslides can cause the slides to flow like a fluid and spread out across surprisingly large areas.

06 Aug 2016

Dating of landslides around Oso reveals recurring patterns

On March 22, 2014, after a period of heavy rain, a hillside near the town of Oso, Wash., collapsed, sending 7.6 million cubic meters of mud and debris across the North Fork of the Stillaguamish River, destroying a rural neighborhood and killing 43 people. The slide took Oso residents by surprise, but scientists say the event was not altogether unexpected, as evidence for dozens of past landslides can be found throughout the Stillaguamish River Valley. New research suggests that large slides have occurred in the Oso vicinity even more frequently than previously suspected.

07 Jun 2016

Comment: Assessing the threat from massive rock slope failures in the Norwegian fjordlands

Records dating back to the Vikings describe large rock avalanches into Norwegian fjords that set off lethal displacement waves. Today, increased development and tourism are exacerbating the risk.

21 May 2016

Pages