Determining contemporary stress directions from neotectonic joint systems

P. L. Hancock
1991 Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences  
A neotectonic joint is a crack which p ropagated in a tectonic stress field th a t has persisted w ith little or no change of orientation until the present day. Investigating neotectonic joints is of value because th e approxim ate orientation of the contem porary stress field can be inferred from them . A lthough exposed neotectonic joints in the flat-lying sedim entary rocks of some cratons are related to regional stress fields, th eir in itiation and propagation occurred close to the E a rth
more » ... lose to the E a rth 's surface. F or exam ple, neotectonic joints in the centre of the Ebro basin (N. Spain) preferentially developed in a thin, near-surface channel sited w ithin a sequence of weak Miocene limestones underlying the upper levels of plateaux. The E bro basin joints strike uniform ly N N W -SSE throughout an area of at least 10000 k m 2 and they are parallel or subparallel to th e direction of greatest horizontal stress extrapolated from in situ stress m easurem ents and fault-plane solutions of earthquakes.
doi:10.1098/rsta.1991.0104 fatcat:5cglznaxprdtfie6fpi2kjciw4