Faults, stresses and mechanics of the upper crust: a tribute to Jacques Angelier

Abstract

Jacques Angelier was born 2 March 1947 in Ales, France. He passed away on 31 January 2010. Jacques was a student at ‘Ecole Normale Superieure’ of Saint-Cloud from 1966 to 1970. He obtained his PhD in 1970 and his DSc in 1979. From 1970–71 Jacques was assistant lecturer at the University Pierre & Marie Curie in Paris (Paris VI), and from 1971–76 assistant lecturer at the University of Orleans. Following his stay in Orleans, Jacques returned to University Pierre & Marie Curie in 1976 as an assistant professor and, from 1981, as a full professor. Jacques worked in Paris until 2003, then moved to the Oceanological Observatory of Villefranche-sur-Mer, also a part of University Pierre & Marie Curie. The main research activities of Jacques Angelier were in the fields of structural geology and geodynamics, with focus on brittle deformation. He was a leader in analysing crustal stresses, that is, in developing methods to understand the various stress fields to which the Earth’s crust has been subjected through time. The basic techniques are inversion of fault-slip data from minor fault sets measured in the field and of focal mechanisms (fault-plane solutions) of earthquakes in a given area to calculate the state of stress. Inversion of fault data is primarily used to infer the so-called “paleostresses”, that is, the state of stress that existed in the past at the time of fault slips. This method relies much on measurements and interpretation of striations on fault planes in the field. Focal mechanisms of earthquakes are used to infer current stresses in active fault zones. Jacques developed computer programs to calculate the stress tensors from these various types of data. Jacques Angelier applied his methods to carry out regional and local brittle-tectonic studies in many countries and regions. These include North Africa, Greece, Turkey, …