( ( Surface ( tiltmeter measurements ) ) ( ( ( ( showed ( refracture orientations ) ) ( at ( oblique angles ) ) ) ( to ( ( the azimuth ) ( of ( the ( initial fracture ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Surface) (NN tiltmeter) (NNS measurements)) (VP (VBD showed) (NP (JJ refracture) (NNS orientations)) (PP (IN at) (NP (JJ oblique) (NNS angles))) (PP (TO to) (NP (NP (DT the) (NN azimuth)) (PP (IN of) (NP (DT the) (JJ initial) (NN fracture)))))) (. .)))
Surface tiltmeter measurements showed refracture orientations at oblique angles to the azimuth of the initial fracture.
(ROOT (S (NP (NNS Tiltmeters)) (VP (VBP are) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NP (DT the) (NN angle)) (PP (IN of) (NP (NP (DT the) (NN slope)) (PP (IN of) (NP (DT a) (NN volcano))))))))))) (. .)))