{'fraction_non_alphanumeric': 0.017424242424242425, 'fraction_numerical': 0.016666666666666666, 'mean_word_length': 5.1157407407407405, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Geologic studies for seismic hazard assessment, Las Positas Fault Zone

Since its existence was reported, the northeast trending Las Positas Fault Zone has been the subject of controversy. Because of proximity of the Las Positas Fault to Lawrence Livermore National Laboratory (LLNL) facilities, geologists from the Laboratory have performed an extensive study of this structure. The Las Positas Fault Zone is best expressed in southeastern Livermore Valley between Arroyo Mocho and the Livermore Oil Field. Here, the informally named northern branch consists of en-echelon shears separating alluvium northwest of the fault from deformed Livermore Formation and uplifted late Pleistocene terrace deposits to the southeast. A /sup 14/C date of 17,400 +- 250 y B.P. was obtained from displaced alluvial deposits. The erosion surface on the lower member of the Livermore Formation has been displaced vertically about 60 m across the northern branch and preserved slickensides indicate oblique but mostly lateral motion. An 85 cm vertical offset of colluvium and possible tectonic creep along the southern branch suggest historic activity on this strand. Net motion is almost entirely lateral. Microseismicity during the period 1969 to 1981 correlates with the south branch of the Las Positas Fault but not the north branch.