Coda Q from educational seismograph network around Koyna–Warna, western India.

We computed the coda wave attenuation (QC) using reservoir-induced seismicity of the Koyna–Warna region in the western part of the Indian shield. We analyzed 484 local seismograms recorded by 16 broadband seismic stations at central frequencies 1.5, 3, 6, 12, and 24 Hz for lapse time window lengths 30s, 40s, 50s, and 60s using the single-backscattering method (Aki and Chouet 1975). The results show that spatial variation of QC, increases from west to east, and north to south in the study region. Our lapse time-dependent of QC estimates are (138.05±37.41)f(1.07±0.07), (191.18±45.24)f(1.00±0.07), (240.07±61.50)f(0.95±0.08), and (299.42±76.32)f(0.88±0.07) for 30s, 40s, 50s and 60s, respectively. The results show that low QC at low frequencies (<3 Hz), which indicates high attenuation at a shallow depth of the region. We compared QC with other regions of the world, as well as in India. Our results are high compared to the earlier studies in the Koyna–Warna region. The frequency-dependent parameter, η is greater than 1, which represents that the study region is seismically active. This study is important for evaluating the source parameters and seismic hazard assessment of the region. Research Highlights: These are the first scientific Qc results obtained using educational seismographs installed in schools in the western part of India. We have used 484 local earthquakes using 16 seismic stations in the Koyna-Warna region for this study. The region shows low QC to the west of compared to east of WGE and it is high for east of Koyna reservoir. The η values are high, varying between 0.76 and 1.19, which indicates the region is heterogeneous and seismically active. The seismic quality factor, QC values are little high and they agree with previous studies in the region. [ABSTRACT FROM AUTHOR]