New aeromagnetic survey data collected over north central Oklahoma image possible seismogenic faults in the crystalline basement. Linear earthquake sequences associated with induced seismicity suggest the reactivation of ancient basement faults, but few of these sequences are aligned with mapped faults. The new data show many earthquake sequences aligned with linear magnetic gradients or offsets between anomalies, while mapped faults, which mainly describe sedimentary cover, show limited correspondence with either. This strongly suggests significant structural differences between the crystalline basement and sedimentary cover. Furthermore, while the earthquakes are occurring on reactivated ancient faults, most of these faults have likely been inactive for millions of years. The magnetic data exhibit many gradient lineaments that are optimally oriented for fault slip, and the earthquake data suggest additional optimally oriented faults. Together these data suggest the presence of potentially numerous seismogenic faults throughout the region, which may contribute to high levels of induced seismicity.

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The dynamic cone penetrometer data had been conventionally used for estimating the base and subgrade California bearing ratio. In recent years, a need for developing mechanistic pavement design procedures has been emphasized. However to develop mechanistic pavement design procedures, measuring engineering properties of pavement layers is essential. Two modifications to the existing dynamic cone penetrometer have been proposed in this paper for obtaining engineering properties of pavement layers. First, an ordinary dynamic cone penetrometer was instrumented with a load cell and an accelerometer to determine the energy imparted to the ground, the resistance to the penetration, and the penetration of the device into the base and subgrade. A second device consisting of a three-dimensional accelerometer embedded in a DCP-like rod was developed to measure modulus and Poisson's ratio of the base and subgrade layers. This device can be placed in the same hole drilled for the first device, thus, requiring minimum coring. Although both devices are proven to be feasible, further analysis is needed for reliably extracting information from these measurements.

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