Monday, November 23, 2015

Re: [californiadisasters] Vasquez Canyon: a new landslide in Santa Clarita, California



That is quite disturbing! Thanks Lin  Mm
 
22 November 2015

Vasquez Canyon: a new landslide in Santa Clarita, California

Posted by dr-dave
10
Vasquez Canyon landslide
A significant landslide has developed in the last few days in Vasquez Canyon, in Santa Clarita in California.  The landslide, which appears to be progressive and has no obvious recent trigger, has caused extensive buckling of the road, which has been closed over a three kilometre stretch.  This image, from the Santa Clarita Valley Signal, provides quite a good general view of the situation beyond the road:
Vasquez Canyon
The landslide, from the Santa Clarita Valley Signal
The landslide has caused impressive damage to the highway:
Vasquez Canyon
Vasquez Canyon road from KTLA5
interestingly, the media are suggesting that this buckling has occurred because the road is moving upwards.  Whilst this might sound a little odd, this excellent drone footage suggests that this might the case:
This is a still from the drone footage of the landslides, showing the damage to the highway:
Vasquez Canyon Road via Youtube
Vasquez Canyon Road via Youtube
This is Google Earth imagery of this section of the road, dated April 2015 – i.e. seven months ago:
Vasquez Canyon
Vasquez Canyon Road via Google Earth
There are clearly some signs of instability in this image, and note the other landslides in the image.  The section of road that has failed is in a box cut, so it would appear that unloading of the slope may be a key factor in the landslide. And interestingly, this imagery from two years ago (May 2013) suggests significant movement at that time as well:
Vasquez Canyon
Vasquez Canyon road in 2013 from Google Earth
And finally, this is Google Street View imagery of the road, taken in 2011:
Vasquez Canyon road
Vasquez Canyon road via Google street view
The extensive deformation in the road was clear even then – indeed the road shows longitudinal cracks along this entire section.  Thus, although this landslide looks very sudden, it has been developing over a prolonged period.
http://blogs.agu.org/landslideblog/2015/11/22/vasquez-canyon-1/




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Posted by: Marilyn Sass <paws_sassy@yahoo.com>


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