{'fraction_non_alphanumeric': 0.013927576601671309, 'fraction_numerical': 0.0, 'mean_word_length': 4.988888888888889, '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}}
Experimental Measurement of the Effects of Acquisition Parameters on DAS Data Quality

Summary Distributed Acoustic Sensing (DAS) is a seismic acquisition method that uses a fibre-optic cable as a sensor. A DAS amplitude measurement involves measuring the difference in the phase of the backscattered light between two positions on the fibre separated by a distance called the gauge length. Each phase measurement is the result of sampling the phase of a shorter section of the fibre using a window whose shape is that of the amplitude envelope of the transmitted laser pulse, often approximated as a Gaussian. As a result of this methodology DAS data has a distinct response, best viewed in the wavenumber domain. The response, in-turn, means that data quality varies significantly based on the acquisition parameters employed. In this paper we show results of the same vertical seismic profile acquired using a variety of different pulse and gauge lengths. The results agree well with theory and demonstrate the importance of the correct choice of DAS acquisition parameters.