Shallow three-dimensional structure investigation of some cities in the Guangdong-Hong Kong-Macao Greater Bay Area

In this project the initial focus was on the core urban area of the GBA, mainly consisting of Guangzhou, Foshan, and Dongguan, with a detection area of 60 × 60 km2. The backbone network with a total of 720 seismic stations spaced 2.25 km apart and an observation duration of 30–35 days was set up. The basic network with a total of 6214 seismic stations spaced 0.75 km apart and an observation duration of 3–10 days was also set up. The backbone network using the broadband seismograph was deployed with a total of 16 seismic stations at 20 km spacing and an observation duration of 30–35 days. The methane detonation source with a total of 63 excitation shots at 7.1 km spacing was fired.