UW geologists create map of major landslides at Oso

UW geologists create map of major landslides at Oso

A team of geologists from University of Washington (UW) has mapped the history of major landslides at Oso using radiocarbon dating, and determined that a massive nearby landslide occurred nearly 500 years ago and not 1,000 years ago as previously thought.

The geologists made an analysis of woody debris buried in various slides at Oso and created the map using radiocarbon dating technology. The method suggested that the slopes at the site have collapsed on average once in every 500 years, and at a higher rate of around once in every 140 years over the last 2,000 years.

The massive mudslide that buried large portion of Oso in March last year was the deadliest landslide in the history of the United States. After that researchers found that the area has experienced several major slides before also, but it was unknown how long ago they happened. Thus, the researchers decided to map the activity in the area.

Geologist Sean LaHusen, a doctoral student in Earth & space sciences at University of Washington, said, “The soil in this area is all glacial material, so one hypothesis is the material could have fallen apart in a series of large landslides soon after the ice retreated, thousands of years ago. We found that that’s not the case — in fact, landslides have been continuing in recent history.”

The team reached the conclusions after unearthing samples of wood buried in the Rowan landslide, just downstream of the Oso, and the Headache Creek landslide, just upriver of the last year’s slide. They also determined that the Rowan landslide, which was nearly five times the size of last year’s Oso slide, occurred 300 to 694 years ago. The Headache Creek slide occurred nearly 6,000 years ago.

The findings of the research published in a recent online edition of the prestigious journal Geology.

In other news Washington reported, University of Washington geologists analyzed woody debris buried in earlier slides and used radiocarbon dating to map the history of activity at the site. The findings, published online Dec. 22 in the journal Geology, show that a massive nearby slide happened around 500 years ago, and not thousands of years ago as some had believed.

The study establishes a new method to date all the previous landslides at a particular location. The method shows that the slopes in the area around Oso have collapsed on average once every 500 years, and at a higher rate of about once every 140 years over the past 2,000 years.

The deadly landslide that claimed the lives of over 40 victims last March in Oso, Washington was not a random occurrence, according to the findings of a new study. Researchers behind the study, whose findings were published on December 22 in the journal Geology, established a new method of dating prior landslides which applies radiocarbon dating to buried debris. Using this new technique, the researchers–primarily affiliated with the University of Washington, but also Portland State University–found that contrary to prior belief, a massive slide had occurred some 500 years ago, reports Immortal

In a statement provided to I4U News, Oso, Washington landslide was the deadliest landslide in the history of US. Researchers claim that the landslide was not a fluke. The region has experienced many major landslides and their can be many more on their way

On March 2014, a major landslide occurred in Oso, Washington which killed more than 40 people and destroyed dozens of homes. It was considered the deadliest landslide in US history.