Attenuation of P and S Waves in the Javakheti Plateau, Georgia (Sakartvelo)

Abstract

The frequency-dependent parameters of attenuation of P and S waves in one of the most seismically active regions, of the Javakheti plateau, have been estimated using digital data for the first time. We have analyzed and processed hundred and fifty local shallow earthquakes that occurred from 2006 to 2018 and were recorded by five seismic stations. The quality factors for P waves ( Q p ) and for S waves ( Q s ) were evaluated by means of the extended coda normalization method. The obtained Q p and Q s are strongly frequency dependent in the frequency range of 1.5 to 24 Hz, and increase with frequency according to the following power laws: Q P = 17.4 ± 2.3 f 1.100 ± 0.033 and Q S = 28.8 ± 3.3 f 1.048 ± 0.039 . The observed Q s / Q p ratio was found to be greater than unity over the entire frequency range, suggesting that scattering may play the main role in the attenuation of body waves on the Javakheti plateau. The frequency dependence of the S wave is very similar to the frequency dependence of the shear wave for another seismically active region of Georgia, the Racha area. A comparison of our results to those other regions of the world shows that among the seismically active areas, the Javakheti plateau is characterized by relatively low values of Q p and Q s , but they are more than volcanic regions such as Etna and Qeshm Island, Iran. The observed results characterize the entire earth’s crust in the study area and will be useful for source parameter estimation, ground motion prediction, and hazard assessment of the Javakheti plateau.

Attenuation of Coda and Body Waves for Tbilisi and Surrounding Area, Georgia

“…Lapse time (s) 7 International Journal of Geophysics V s /V p . Such a result is observed in many regions of the world with a high degree of lateral heterogeneity [3,[47][48][49][50][51]. We observed similar results for another more seismically active region, the Javakheti volcanic plateau, where the Q s /Q p ratio varies in the range of 1.4-1.6 (Figure 8(a)) [51].…”

“…Such a result is observed in many regions of the world with a high degree of lateral heterogeneity [3,[47][48][49][50][51]. We observed similar results for another more seismically active region, the Javakheti volcanic plateau, where the Q s /Q p ratio varies in the range of 1.4-1.6 (Figure 8(a)) [51]. The values of Q p and Q s along the frequency for three regions of Georgia are given in Figure 8(b).…”

“…Thus, we will be able to regionalize almost the entire territory of Georgia according to the Q parameter. ; line 2-Erzincan, Turkey [5]; line 3-Yunnan Province, China [57]; line 4-Racha, Georgia [46]; line 5-the Javakheti plateau, Georgia [51]; line 6-Arunachal Himalaya [8]; line 7-Tbilisi region (this study); line 8-the Bam region, Iran [58]; line 9-Northwest Caucasus [21]; line 10-Central Asia [59]; line 11-the Andaman Sea [7]. ; line 2-Umbria-Marche, Italy [41]; line 3-Racha, Georgia [46]; line 4-Arunachal Himalaya [8]; line 5-Tbilisi region (this study); line 6-W. Greece [60]; line 7-Andaman Sea [7]; line 8-Bam region, Iran [58]; line 9-Delhi, India [61]; line 10-Alborz region, Iran [62].…”

“…Figure 9: Comparison of Q c for different regions: line 1-Etna, Italy[56]; line 2-Erzincan, Turkey[5]; line 3-Yunnan Province, China[57]; line 4-Racha, Georgia[46]; line 5-the Javakheti plateau, Georgia[51]; line 6-Arunachal Himalaya[8]; line 7-Tbilisi region (this study); line 8-the Bam region, Iran[58]; line 9-Northwest Caucasus[21]; line 10-Central Asia[59]; line 11-the Andaman Sea[7].…”