Continuous Waveform Analysis of Offshore DAS Arrays for Automatic Earthquake Detection and Magnitude Estimation in the UKCS

A reliable, long-term seismic monitoring system near the large-scale carbon storage areas recently licensed in the North Sea and other offshore areas in the UK and other countries in northern Europe, is essential to guarantee safe injection and storage operations. In offshore areas, permanent seismic monitoring systems could either be based in nearby monitoring wells and/or on conventional ocean bottom seismometer arrays. Alternatively, offshore DAS arrays could provide a more cost-effective seismic monitoring solution. In this study, we assess the passive waveform dataset recorded continuously for one month by an offshore DAS array in the UK Southern North Sea operated by Tampnet, to automatically detect and characterise seismic events. This DAS array is located just south of some carbon storage areas recently licensed by the UK NSTA, making it suitable for long-term monitoring of CO2 injection once the injection wells are fully operational in the following years.