Carbon dating of the woody debris found along the Rowan landslides has led the researchers to believe that a huge landslide affected the area approximately 500 years ago. The researchers collected samples from various sites, including the region upstream from the Oso landslide site and downstream of the landslide that took place in the year 2014.
The entire stretch of region amounts up to about 6 kilometers. Interestingly, till date it was believed that the massive landslide around the region took place about thousands of years ago, but to the study it seems that it was just approximately about 500 years ago.
According to the statement given by Sean LaHusen, a doctoral student of Earth and Space sciences, “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”.
The study shows an indication that the materials found along the Oso site are approximately about 2000 years old, while the materials along the headache creek date back up to 6000 years. On the other hand, their findings also suggest that every 140 years, the Oso site experiences massive landslides. This has lead to confusion with regard to the accurate period of the occurrences.
Alison Duvall, an assistant professor of Earth and Space Sciences stated that the confusion about the accurate period of the landslides is because of the variation of the age derived from the various materials. Some of them are approximately about hundreds of years old, while some date back to thousands. The reason might just be the frequent landslides that occur along the region. The landslides encapsulate the things on the surface while bringing in top the buried ones.