28 September 2016
Rizhao rockslide: a narrow escape in a new public park in Shandong, China
Posted by Dave Petley
Rizhao rockslide in Shangdong
The city of Rizhao in Shangdong, Eastern China has had an exceptionally lucky escape this week when a rockslide occurred in a new public park, shortly before it was due to open. The location is Phoenix Mountain in the centre of the city; the Park was due to open “later this month”. The rockslide itself is somewhat dramatic, as this image from The Nanfang shows:-
A view of the rockslide from a different angle looks no less dramatic:
According to the article, this slope had been turned into a rock climbing facility, and the area to the right of the landslide shows evidence of extensive slope engineering. I assume that this extended into the area that has failed, although it is not possible to say what it looked like. The failure itself appears to have been structurally controlled. Note the very large boulder sizes. Needless to say, if this landslide had occurred a month later the impact could have been very dramatic, with losses on the slope, in the park and in the parking area. The article makes some interesting observations about cause:
Zhang Bao, director of Lanshan District emergency services, said a preliminary investigation has determined that the landslide was a natural phenomenon, and not man made. However, Zhang did not answer questions as to why the park facilities are located so close to the mountain, or if any studies or investigations were conducted prior to the construction of the rock climbing facility.
That is a courageous conclusion in an area that has clearly had extensive slope works. Unfortunately as yet I have been unable to precisely locate this massif on Google Earth, so as yet cannot give an indication as to what this site was like before they works were undertaken. My best guess (and it is no more than that) is that it is this site, the image is from last year:
some before pics via the link below. It’s certainly hard to identify the precise location!
This is the location of the slide: 35.104169° 119.324784°
The location in the news report is difficult to follow, but the hill is in Lanshan City not Rizhao.
Most recent Google earth image is from 2013. The Jan 2012 image is better.There has been significant work at the site.
The round building near the soccer pitch is clearly visible in photos of the site from http://w.dzwww.com/p/446586.html
My guess would be a large wedge style failure. Bedding is clearly visible and would be in a toppling geometry, but the failure plane appears to be on an inclined joint. In such an arrangement removal of material at the toe could provide a release mechanism.