How do we understand distant history and the future of earthquakes through the surface of landscape and through documentary film?
The black and white documentary film ‘Pseudotachylyte’ (54 min, 28 sec) portrays how scientists explore landscape; through the microscopic view of the world to an understanding of deep time.
In 2017, a team of international geo-scientists investigated the Arctic landscape of the Lofoten Islands in Norway in order to examine causes of earthquakes originating deep below earth’s surface. In an exceptionally well-preserved field site, this natural laboratory provides a rare ’window’ into these exposed rocks that were once deep below the surface of the earth and the ocean. The rocks formed more than 2 billion years ago, almost half the age of planet Earth.
Most earthquakes occur in the upper 20 km of the earth’s crust, where rocks are cold, brittle and elastic, and able to build up the tectonic stresses released in sudden earthquakes.
Below this depth, the lower crust is hotter and rocks there typically deform plastically and steadily, rarely accumulating enough stress for large earthquakes.
Despite this, some of the largest earthquakes initiate in the lower crust.
The aim of this expedition was to improve the understanding of these deeper and potentially devastating earthquakes by mapping out the fault zone network and assessing where and when geologically ancient earthquakes occurred.
Ultimately, information derived from these ancient fault roots will be used to infer processes occurring at depth along faults that are currently active in modern earthquake zones.