Seismic noise between 0.003 Hz and 1.0 Hz and its classification

Progress in Earth and Planetary Science

Table 1 Forcing mechanisms of various seismic noise in three categories

	Frequency range (Hz)	Category 1		Category 2	Category 3
		PSW ocean		PSW land	QS
		DI	WW
Primary MS	0.05–0.07	O
Secondary MS	0.1–0.3		O
Hum	0.003–0.015	O
TC in the Ocean	0.15–0.25		O
Stormquakes	0.02–0.05	O
Weather Bomb	0.01–0.02		O
Wind ocean waves	0.3–2.0		O
Tornado	0.01–0.03			O
TC on Land	0.01–0.03			O	?
Pressure loading deformation on land and seafloor	0.01–0.05				O

Category 1 is Propagating Seismic Waves (PSW) from ocean sources. Category 2 is PSW from on-land sources and Category 3 is the quasi-static deformation (QS). Category 1 is divided into two cases, the Direct Interaction between ocean waves and solid Earth (DI) and the Wave–wave interaction among ocean waves (WW). MS is Microseism, and TC is Tropical Cyclone