37 A Window into Regional Deformation and Sedimentation through Geo-, Thermo-, and Petrochronology (Posters)

Friday, 29 March 2019
1:00 PM - 5:00 PM
Carolina Ballroom

NEAR-SURFACE GEOPHYSICAL INVESTIGATION OF A HYPOTHESIZED QUATERNARY-ACTIVE SHEAR ZONE ACCOMMODATION: NEW MADRID SEISMIC ZONE

Paper number: 37-12
Program: Theme Sessions
Time: 1:00 PM – 5:00 PM

Authors

Abstract

Strain accommodation and geographic fault location are two seismic hazard parameters, among others, poorly defined in the New Madrid seismic zone (NMSZ). A recent series of seismic-reflection profiles acquired 12-km northeast of the Reelfoot stepover and along the central axis of the Reelfoot rift imaged steeply dipping N 30° E striking faults with transpressional displacement. Projecting these features northeast 22 km to their intersection with the nearest available subsurface dataset (i.e. a low-resolution industry seismic reflection profile) found a discrete set of faults with similar characteristics. Conversely, the 12 km southwest back-projection of the faults intersects the Reelfoot stepover near the community of Proctor City (TN), where the Reelfoot scarp displays a distinct lateral discontinuity in an otherwise linearly coherent orientation. A prior low-resolution seismic reflection profile present at this location also exhibits a transpressional fault structure affecting the tops of the deeper Cretaceous and Paleozoic horizons; however, Quaternary stratigraphy were not resolved at either site. Newly acquired near-surface geophysical surveys across both these fault sets show Quaternary-active deformation based on local seismic stratigraphy. A third seismic-reflection dataset acquired along the projected strike of the fault zone exhibited similar deformation, providing additional evidence for a correlative relationship of a previously unknown 34-km-long northeast-oriented transpressional fault zone coincident with the hypothesized northeast continuation of the NMSZ’s southern Axial shear zone across the Reelfoot fault.

Geological Society of America Abstracts with Programs. Vol. 51, No. 3

doi: 10.1130/abs/2019SE-327531

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