Electronic Supplement to
Data Quality of Collocated Portable Broadband Seismometers Using Direct-Burial and Vault Emplacement

by Kasey Aderhold, Katherine E. Anderson, Angela M. Reusch, Mary C. Pfeifer, Richard C. Aster, and Tim Parker

The supplementary material for this paper contains figures of the daily median noise levels in the microseism band, monthly probability density functions (PDFs) for the magnitude-squared coherence between the six station couplings (direct-burial 1 to direct-burial 2, vault 1 to direct-burial 1, vault 1 to direct-burial 2, vault 1 to vault 2, vault 2 to direct-burial 1, and vault 2 to direct-burial 2) for all three components (BHE, BHN, and BHZ), results of the coherency self-noise analysis, and the recordings of the teleseismic and local earthquakes used for the signal-to-noise analysis.

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Figures

Figure S1. Daily median noise levels on the microseism band (2–20 s) with respect to the new low-noise model (NLNM; Peterson, 1993) for eight months of study (1 January–31 August 2012) on all four stations. Vertical dashed lines indicate days on which an M_w ≥ 7 earthquake occurred (PSD, power spectral density).

Figure S2. Results from rotation in the horizontal plane relative to vault 1 to correct for orientation errors using recorded data from the entire month of December 2011. Rotations were 3.1° for direct-burial 1, −2.4° for direct-burial 2, and −4.4° for vault 2 clockwise from north. Median PSDs of all noise are in solid lines, and median PSDs of uncorrelated installation and instrument noise are in dashed lines.

Figure S3. Results from dip and azimuth vertical rotation for the four stations to correct for nonparallel vertical components using recorded data from the entire month of December 2011. Rotations were 0.2°/10° for vault 1, 0.35°/175° for vault 2, 0.4°/20° for direct-burial 1, and 0.3°/125° for direct-burial 2 for dip and azimuth (clockwise from north), respectively. Median PSDs of all noise are in solid lines, and median PSDs of uncorrelated installation and instrument noise are in dashed lines.

Figure S4. (top) Normalized and band-pass-filtered teleseismic seismograms on the BHZ component at the four stations for all 23 M_w≥ 6.0 earthquakes between 30° and 90° distance from the study site. The black vertical line shows the P arrival picks, with the noise window to the left, the signal window to the right, and the date of the event on the bottom left. (bottom) Focal mechanisms of the moment tensors from the Global Centroid Moment Tensor catalog (Ekström et al., 2012) for the M_w≥ 6.0 earthquake from January to August 2012. Black focal mechanisms were used for the signal-to-noise calculations, and gray focal mechanisms were not.

Figure S5. Normalized and high-pass-filtered seismograms for the six 1.1 ≥ M_L ≥ 0.1 local earthquakes recorded on the four stations. The handpicked first arrival is indicated by the solid line, and the 1 s noise and signal windows are shown with the dashed lines. The date of the event is indicated in the lower left corner. For magnitudes, refer to Table 3 in the main article.

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Animations

Animation S1 [Animated GIF; ~613 KB]. Animation of the PDF of the magnitude-squared coherence on the BHZ component. The PDF is taken of the hourly magnitude-squared coherences for each month from January to August 2012 for each of the six station pairings. (First column from top to bottom: direct-burial 1 to direct-burial 2, vault 1 to direct-burial 1, and vault 1 to direct-burial 2. Second column from top to bottom: vault 1 to vault 2, vault 2 to direct-burial 1, and vault 2 to direct-burial 2.) The x axis is the log₁₀ of frequency, the y axis is magnitude-squared coherence, and the black line is the median of the PDF.

Animation S2 [Animated GIF; ~634 KB]. Animation of the PDF of the magnitude-squared coherence on the BHE component. The PDF is taken of the hourly magnitude-squared coherences for each month from January to August 2012 for each of the six station pairings. (First column from top to bottom: direct-burial 1 to direct-burial 2, vault 1 to direct-burial 1, and vault 1 to direct-burial 2. Second column from top to bottom: vault 1 to vault 2, vault 2 to direct-burial 1, and vault 2 to direct-burial 2.) The x axis is the log₁₀ of frequency, the y axis is magnitude-squared coherence, and the black line is the median of the PDF.

Animation S3 [Animated GIF; ~627 KB]. Animation of the PDF of the magnitude-squared coherence on the BHN component. The PDF is taken of the hourly magnitude-squared coherences for each month from January to August 2012 for each of the six station pairings. (First column from top to bottom: direct-burial 1 to direct-burial 2, vault 1 to direct-burial 1, and vault 1 to direct-burial 2. Second column from top to bottom: vault 1 to vault 2, vault 2 to direct-burial 1, and vault 2 to direct-burial 2.) The x axis is the log₁₀ of frequency, the y axis is magnitude-squared coherence, and the black line is the median of the PDF.

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