LDEO Seismology: Long-Period Noise

SDP-CI , LHN

Noise Levels at Different Periods

The table below gives the decibel 10% noise level (in db) for each month in several period bands. The 10% noise level is defined as the signal level not exceeded 10% of the time, based on hourly measurements. Each entry in the table is color coded with reference to the New Low Noise Model (NLNM, Peterson, 1993):
navy, -6 db < value-NLNM < -3 db
blue, -3 db < value-NLNM < 3 db
aqua, 3 db < value-NLNM < 6 db
lime, 6 db < value-NLNM < 9 db
yellow, 9 db < value-NLNM < 12 db
orange, 12 db < value-NLNM < 15 db
red, 15 db < value-NLNM < 20 db
fuchsia, 20 db < value-NLNM < 25 db
silver, value-NLNM < -6 db, value-NLNM > 25 db

Black indicates that there was an insufficient number of hourly measurements to calculate a noise level.

Noise levels (PSD) in decibels
Month Chan. Qual. # obs. 268s 228s 193s 164s 139s 118s 100s 85s 72s 61s 52s 44s 37s 32s 27s 23s 19s 16s 14s 12s 10s

200608 LHN AR 354 -139 -139 -140 -140 -141 -142 -143 -144 -145 -146 -147 -148 -149 -149 -150 -151 -150 -149 -149 -150 -146

200607 LHN AR 744 -142 -143 -144 -145 -146 -147 -148 -149 -151 -152 -153 -153 -155 -155 -155 -155 -153 -149 -149 -149 -142

200606 LHN AR 693 -138 -138 -140 -140 -141 -142 -143 -144 -145 -146 -147 -149 -150 -151 -152 -152 -151 -147 -148 -149 -139

200605 LHN AR 674 -139 -139 -141 -142 -143 -144 -146 -147 -148 -149 -150 -151 -152 -154 -155 -156 -153 -149 -148 -147 -141

200604 LHN AR 719 -139 -139 -142 -143 -144 -145 -147 -147 -148 -150 -151 -152 -153 -154 -156 -155 -154 -150 -148 -146 -142

200603 LHN AR 741 -136 -137 -138 -139 -141 -142 -143 -145 -146 -147 -148 -149 -150 -150 -151 -152 -151 -147 -144 -143 -140

200602 LHN AR 666 -139 -140 -142 -143 -145 -146 -147 -148 -149 -151 -152 -152 -153 -154 -155 -154 -151 -146 -145 -146 -140

200601 LHN AR 744 -136 -137 -138 -140 -141 -143 -144 -145 -146 -147 -148 -149 -150 -151 -152 -151 -147 -144 -142 -142 -133

Month	Chan.	Qual.	# obs.	268s	228s	193s	164s	139s	118s	100s	85s	72s	61s	52s	44s	37s	32s	27s	23s	19s	16s	14s	12s	10s
200608	LHN	AR	354	-139	-139	-140	-140	-141	-142	-143	-144	-145	-146	-147	-148	-149	-149	-150	-151	-150	-149	-149	-150	-146
200607	LHN	AR	744	-142	-143	-144	-145	-146	-147	-148	-149	-151	-152	-153	-153	-155	-155	-155	-155	-153	-149	-149	-149	-142
200606	LHN	AR	693	-138	-138	-140	-140	-141	-142	-143	-144	-145	-146	-147	-149	-150	-151	-152	-152	-151	-147	-148	-149	-139
200605	LHN	AR	674	-139	-139	-141	-142	-143	-144	-146	-147	-148	-149	-150	-151	-152	-154	-155	-156	-153	-149	-148	-147	-141
200604	LHN	AR	719	-139	-139	-142	-143	-144	-145	-147	-147	-148	-150	-151	-152	-153	-154	-156	-155	-154	-150	-148	-146	-142
200603	LHN	AR	741	-136	-137	-138	-139	-141	-142	-143	-145	-146	-147	-148	-149	-150	-150	-151	-152	-151	-147	-144	-143	-140
200602	LHN	AR	666	-139	-140	-142	-143	-145	-146	-147	-148	-149	-151	-152	-152	-153	-154	-155	-154	-151	-146	-145	-146	-140
200601	LHN	AR	744	-136	-137	-138	-140	-141	-143	-144	-145	-146	-147	-148	-149	-150	-151	-152	-151	-147	-144	-142	-142	-133