Australia: The Land Where Time Began

A biography of the Australian continent 

Millennial-Scale Landslide record in Andes Consistent with Being Triggered by Earthquakes

Rare glimpses of landscapes that are evolving under the influence of tectonics and climate are provided by geological records of landslide activity. According to McPhillips et al. (2014) it is common to reconstruct landslide activity in the geologic past by the use of historic landslide inventories, as the individual landslide deposits are not likely to be preserved. Landslide deposits have been interpreted as proxies for palaeoclimates relating to precipitation changes, though landslides can also be triggered by earthquakes. In this paper McPhillips et al. (2014) measured the cosmogenic concentration of ¹⁰Be in individual cobbles from the modern channel of the Quebrada River and an adjacent terrace in Peru and calculated rates of erosion. Their results, in conjunction with a ¹⁰Be production model, indicated that the concentration of ¹⁰Be in each cobble population recorded the erosion over thousands of years and are consistent with a landslide origin for the cobbles. Prior to about 16,000 years ago, during the relatively wet climate, the ¹⁰Be concentration distribution in terrace cobbles is indistinguishable from the distribution in the river channel cobbles produced during the drier climate of the past few thousand years. It is suggested by this that there has been no change in the amount of erosion from landslides in response to changes of climate. It is implied that the integrated, millennial-scale landslide record of McPhillips et al. implies that in the arid foothills of Peru the primary trigger of landslides may be earthquakes.

Sources & Further reading

McPhillips, D., P. R. Bierman and D. H. Rood (2014). "Millennial-scale record of landslides in the Andes consistent with earthquake trigger." Nature Geosci 7(12): 925-930.