Table 1. Sound levels of the pressure excitation exposures applied in the pilot experiments.

Stage	Measured sound levels			Strikes	Distance (m)
	Lz−p	SELss	SELcum
	(dB re µPa2)	(dB re1 µPa2s)	(dB re µPa2s)
1	198	175	175	1	800
	211	187	187	1	100
	211	187	204	50	100
2	206	181	204	200	200
	210	186	203	50	100
	210	186	206	100	100
3–4a	205	181	206	300	200
	210	186	196	10	100
	210	186	206	100	100

L_z−p  =  zero to peak sound pressure level, SEL_ss  =  single strike sound exposure level and SEL_cum  =  cumulative sound exposure level, see the text for further explanation. The last 2 columns present the corresponding distance from a ‘typical’ North Sea pile-driving installation and number of strikes.