Advanced seismic imaging techniques characterize the Alpine Fault at Whataroa (New Zealand)

摘要: The plate-bounding Alpine Fault in New Zealand is a 850 km long transpressive continental fault zone that late its earthquake cycle. We have acquired and processed reflection seismic data to image the subsurface around main drill site of Deep Drilling Project (DFDP-2). resulting velocity models images upper 5 show complex structures zone. most prominent feature strong reflector at depths 1.5-2.2 with an apparent dip 48° to southeast below DFDP-2 borehole, which we assume be trace Fault. Above reflector, parallel reflectors suggest presence ∼600 m wide damage Additionally, subparallel are imaged interpret as secondary branches Conjugate faults by complexity subsurface. derived P-wave model reveals 300-600 thick sedimentary layer velocities ∼2.3 km/s above schist basement 4.5-5.5 km/s. A low-velocity can observed within 0.8-2 depth. small-scale anomaly appears top correlated results provide reliable basis for characterization used further structural geological investigations architecture this area.