18 March 2015
Yeager airport fill slope failure: the landslide history
Posted by Dave Petley
Yeager Airport fill slope failure
Movement of the Yeager Airport fill slope failure appears to have ceased and the residents of Keystone Drive have now been allowed back to their homes. There is a great deal of interest in the causes of the landslide, which remain far from clear, and in the approach that will be taken to mitigating the slope so as to protect (and presumably rebuild) the EMAS at the end of the runway. John Boyle has been undertaking some digging into the landslide history of this site; Bill Murphy at Leeds has been kindly keeping me in the loop. Two interesting aspects have emerged. The first is on a Facebook site, which includes several interesting comments from past and present residents of Keystone Drive. Key comments include the following (I have included just the key pieces of information needed to understand the site):
Robert Harrah: “…they covered up a natural spring on that hill that we played in as kids”
Terina Joe Adkins “This isn’t the first time folks. My grandparents house went over in a mudslide on Keystone 45 years ago d… Roll forward 45 years and it’s happened again…”
Kelly Stricker Spurlock “Terina, I remember that. I was just a kid when that happened. I had a friend, Sharon Koon, who also lost a house then. Did your grandparents house sit on the side of the airport just above where the church was?”
Kelly Stricker Spurlock “Almost exact same spot for the slide then and now!”
Terina Joe Adkins “Kelly, yes my grandparents, Bud and Evelyn Hill’s house sat on the side of the airport just up from the church. Almost in the exact place this slide us. My mom, Barbara talks about The Koons.”
This is backed up by a newspaper report from Charleston Gazette on 19th March 1973. Whilst the image (and indeed the caption) have not reproduced well, the implications are clear:
Kanawha Airport was renamed Yeager Airport. This Google Earth image is from 2003, before the EMAS works:
Even allowing for the distortion of the image caused by the low quality ground model in Google Earth, it is no surprise that this slope has a history of landslides. I wonder how this was taken into account in the construction of the fill slope.
It seems this project is suffering from an inadequate global stability. Increased soil moisture is a likely contributor, my opinion is the the toe of an unstable slope was overloaded, inducing solifluction under the key trench. As Dr. Terry Howard, College of Mines and Earth Resources, University of Idaho said, the problem is usually caused by moisture .
Looking at the available construction photos it seems there was no drainage installed! Saturated and simply slip down!