Atle Rotevatn

How do normal faults grow?

In this geolunch talk, Atle will tell us about how he and some of his  friends/co-authors decided to have a stab at figuring out how normal faults actually grow while he was on sabbatical in New Zealand. As you may or may not know, there has been two dominating world views on how normal faults grow. In the simplest terms these are the two models: The first model claims that when faults accumulate displacement they also lengthen by tip propagation – this is a nice way to explain the good correlation between displacement (D) and length (L) over several orders of magnitude.

The second model claims that faults first lengthen very quickly and subsequently accumulates displacement without further lengthening of the faults; critics of this model may argue that it disagrees with D-L scaling, but as will be shown in this talk it actually does not. Anyway, during his stay in NZ Atle and his friends stated digging through lots of published fault data, replotting their growth paths in D-L space. They also added data from faults from analogue models to compare with the natural faults. The results were very interesting indeed – so interesting that they were published in JSG recently

(https://www.sciencedirect.com/science/article/pii/S0191814118304103). Atle will tell us more about this in the talk – but also about how some great discussions came about from showing their data on Twitter for the whole geotweep community to see before any of it was published. These discussions led to revisions to the paper and is an example of how social media can be used not only for outreach, but also for peer-review and scientific discussion.