The Jiangsu Earthquake Agency announced on the 11th that the province is exploring a new model of seismic monitoring on offshore wind power platforms and has completed the construction of a marine seismic monitoring network.

According to the introduction, Jiangsu has a coastline of nearly 1,000 kilometers and a vast sea area. The geological environment of the Yellow Sea is complex, and the Subei-Binhai Fault, with a total length of 270 kilometers, lies 20 to 30 kilometers off the coast of Yancheng.

Marine seismic monitoring has long been a major challenge in seismic monitoring work. On November 17, 2021, a magnitude 5.0 earthquake occurred in the sea area of Dafeng District, Yancheng, which not only caused widespread shaking on the nearby land but also affected important facilities operating at sea. The Jiangsu Earthquake Agency sought a breakthrough in solving this problem from this marine earthquake.

A wind power platform equipped with seismic monitoring instruments. Photo provided by the Jiangsu Earthquake Agency

With the support of offshore wind power enterprises, the Jiangsu Earthquake Agency selected an offshore wind farm 45 kilometers from the Dafeng coastline. Based on surveys of the observation environment, communication network, power supply, and operation and maintenance support, it installed a seismometer and a strong-motion seismometer on the wind power platform and wind turbine foundation piles respectively, obtained continuous observation data, and carried out calculations and analyses of background noise and monitoring capability.

On November 14, 2022, the seismometer mounted on the offshore wind power platform clearly recorded a magnitude 3.8 earthquake in the sea area of Sheyang, Yancheng, 105 kilometers away, which practically verified the feasibility of conducting seismic monitoring based on offshore wind power platforms. The new model of seismic monitoring on offshore wind power platforms has effectively solved the three major problems restricting marine seismic monitoring—power supply, communication, and operation and maintenance—opening up a new path for marine seismic observation and has been incorporated into the relevant plans of the China Earthquake Administration for marine seismic observation.

At present, the Jiangsu Earthquake Agency has built 7 observation stations on offshore wind power platforms. Together with the province's original 3 island observation stations, they form a marine seismic monitoring network comprising 10 observation stations and 16 sets of seismic equipment. After the network was established, the aperture of Jiangsu's marine seismic monitoring network extended 70 kilometers into the sea area, and the positioning accuracy of sea-area earthquakes improved from Class IV to Class II, greatly enhancing marine seismic monitoring capability and achieving the operational running of Jiangsu's marine seismic monitoring station network.

In the future, the Jiangsu Earthquake Agency will build a "trinity" seismic safety service system integrating marine seismic monitoring and early warning, research on key technologies, and safety monitoring and assessment of offshore wind power engineering, and create a comprehensive marine seismic observation system for Jiangsu.