I came across a very interesting analysis of some of the surface effects of the earthquake in New Zealand last September. Writing in 'The Landslide Blog' on the American Geophysical Union Web site, Prof. Dave Petley reports:
The farmer at this site very kindly allowed us to enter his field ... where the array of cracks, and associated deformation, is astonishing. GNS have an aerial view of the field.
... below is the ground view:
. . .
A few more kilometres to the west and we are into the maximum displacement area. Here we see over 3 metres [almost 10 feet] of horizontal deformation and about 1.5 metre [almost 5 feet] vertically. This is the view from the hanging wall side – the drop down onto the footwall, and the lateral motion should be evident:
The picture below was taken on the footwall side looking back towards the fault – note the horizontal motion (the road has been patched up) and the vertical change. Remember that this was a straight road across a flat plain before the earthquake:
There's much more at the link, including more photographs. In a follow-up report, Prof. Petley provides photographs of the damage done to a railway line by the earthquake. Here's one of them.
That's quite a bend! I hope no train came along before it was spotted and the line closed . . . otherwise things might have got very interesting, very quickly! I find it fascinating how the horizontal and vertical shift occurred along the line of the fault beneath the earthquake zone, almost in a straight line across the countryside. Prof. Petley provides a map that shows how it ran.
If you, like me, are interested in how earthquakes move things around, and change the landscape, both reports are well worth reading.