The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
On 7 April 2024, a major valley-blocking landslide was triggered by blasting in a quarry at Bijela near Mostar in Bosnia. There is a report about this event in the Sarajevo Times.
Remarkably, this landslide was also captured on a video, which is available on Youtube:-
The video shows the blast at about 1 minute into the footage:-
Immediately, a section of the slope behind the blast starts to slide:-
Note also that a block nearer to the camera also fails and fragments. The failure very rapidly extends upslope, beyond the quarry boundary.
The front of the landslide very rapidly fragments, and as the failure enters the river it generates a ferocious displacement wave:-
There is a version of the video that better captures the impact of the displacement wave, which is worth viewing.
So, a few points to note about this landslide. First, the image at the blast occurs appears to show a smooth surface above the block that failed that is inclined towards the quarry – I would interpret this as a joint. If so, this suggests to me that the rock slope potentially had a a discontinuity set that was favourable to sliding. This is supported by post-failure photographs. Thus, debuttressing the slope through a blast at the toe looks perilous.
Second, the lateral shear for the major block that failed is also visible before the blast (take a look at the first image above), so the release surface on this side of the landslide was also already present.
Third, the lateral shear for the minor block that failed was also visible before the blast.
Finally, the power of the displacement wave is startling. It is very fortunate that the impact of the landslide was only two people injured and the loss of some cars.
There is now an investigation being undertaken into the landslide, but a focus will need to be on the assessment of the stability of the slope before the blast.
Images posted online also suggest that the valley is blocked. This will need urgent attention.
