EARTHQUAKES AND EXPLOSIONS 

 BIOLOGICS - 



PRECIPITATION — 



SHIPS, INDUSTRIAL 



ACTIVITY 



SURFACE 

 WAVES, v 

 SECOND- X, 

 ORDER 

 PRESSURE 

 EFFE CTS (SEISMIC 



BUBBLES AND SPRAY 

 (SURFACE AGITATION) 



BACKGROUND) 



-20 



INTERMITTENT AND 

 LOCAL EFFECTS 



PREVAILING NOISES 



_ WIND-DEPENDENT BUBBLE 

 AND SPRAY NOISE 



s USUAL TRAFFIC NOISE, DEEP 

 = WATER 



HI USUAL TRAFFIC NOISE, SHALLOW 

 WATER 



EXTRAPOLATIONS 



LIMITS OF PREVAILING NOISE 

 THERMAL NOISE 



LOW-FREQUENCY, VERY- 

 Wmmm SHALLOW-WATER WIND 

 DEPENDENCE 



HEAVY TRAFFIC NOISE 



HEAVY PRECIPITATION 



GENERAL PATTERN OF NOISE 



FROM EARTHQUAKES AND 



EXPLOSIONS 



10 



10- 



10 J 10 



10 



FREQUENCY, C/S 



Figure 2. Ambient-noise speatra, summarizing results and cone/ usions con 

 spectrum shape and level and probable sources and mechanisms of the ambi 

 various parts of the spectrum between 1 c/ s and 100 kc/s. 



