Ambient noise levels in Gujarat State (India) seismic network

Figures & data

Table 1. Online broadband seismograph (BBS) seismic stations of GSNet and local geology.

Serial no.	Station	Code	Instrument	Geology	Latitude (°)	Longitude (°)	Region
1	Naliya	NAL	Guralp CMG-3T	Limestone	23 19 63 N	68 49 66 E	Kachchh/Bhuj
2	Badargarh	BAD	Guralp CMG-3T	Sandstone	23 27 96 N	70 37 11 E	Kachchh/Bhuj
3	Chobari	CHO	Guralp CMG-3T	Quaternary	23 30 78 N	70 20 61 E	Kachchh/Bhuj
4	Radhanpur	RAD	Guralp CMG-3T	Quaternary	23 49 19 N	71 37 03 E	North Gujarat
5	Gandhinagar	GND	Guralp CMG-3T	Quaternary	23 12 12 N	72 38.92 E	South Gujarat
6	Jhagadia	JAG	Guralp CMG-3T	Tertiary	21 43 55 N	73 09.08 E	South Gujarat
7	Valsad	VAL	Guralp CMG-3T	Basalt	20 13 02 N	73 26 87 E	South Gujarat
8	Ukai	UKE	Guralp CMG-3T	Basalt	21 13 32 N	73 35 06 E	South Gujarat
9	Kadana	KAD	Guralp CMG-3T	Lunavada (Quartzite)	23 17 22 N	73 51 23 E	South Gujarat
10	Morbi	MOR	Guralp CMG-3T	Basalt	22 50 33 N	70 53 62 E	Saurashtra
11	Rajkot	RAJ	Guralp CMG-3T	Basalt	22 21 41 N	70 45 83 E	Saurashtra
12	Una	UNA	Guralp CMG-3T	Basalt	20 58 65 N	70 55 58 E	Saurashtra
13	Bhavnagar	BHV	Guralp CMG-3T	Basalt	21 41 61 N	70 58 80 E	Saurashtra
14	Surendranagar	SUR	Guralp CMG-3T	Sandstone	22 43 09 N	71 35 09 E	Saurashtra

Figure 1. Geology of the Gujarat showing the permanent online seismic stations used for the study. Available in colour online.

Figure 2. Block diagram showing the design of the vault room in which the installation of CMG-3T has been carried out and the recording room at the Permanent Broadband Seismograph Station. Available in colour online.

Figure 3. A sample record of the 1 hour of seismic background noise (SBN) at the permanent seismic station Naliya on the limestone. Available in colour online.

Figure 4. Comparison of the vertical component median seismic noise of 14 stations with the US Geological Survey high and low noise models of Peterson (1993). The power spectral densities (PSDs) are in units of dB with respect to acceleration (reference level 1(m/s²)²/Hz). The grey lines represent the noise spectra of 30-min time windows and the dark lines represent the medians of these. The station codes are at the top of each figure.

Figure 4. (Continued).

Figure 5. (a) Day and night comparison of the vertical component median seismic noise of 14 stations. The power spectral densities (PSDs) are in units of dB with respect to acceleration (reference level 1 (m/s²)²/Hz. The station codes are at the top of each figure. (b) Day and night comparison of the vertical component median seismic noise of 14 stations. The PSD is in units of dB with respect to acceleration (reference level 1 (m/s²)²/Hz. The station codes are at the top of each figure. Available in colour online. Available in colour online.

Figure 5. (Continued).

Peterson , J. 1993 . “ Observations and modeling of seismic background noise ” . US Department of Interior Geological Survey, 93-322, Open-File Report .

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