Geochemical Characteristics of Soil Gas and Strong Seismic Hazard Potential in the Liupanshan Fault Zone (LPSFZ)

Abstract

Eight soil gas measurements were performed in the Liupanshan fault zone (LPSFZ) to observe the concentration and flux of soil gas radon (Rn) and CO2 in October 2017 and October 2018. By combining the historical strong earthquake background and modern seismic activity of the fault zone, the relation between the geochemical distribution characteristics of soil gas and the seismicity of the fault zone was studied herein. Furthermore, the strong seismic hazard potential of the fault zone was discussed. Results show that the concentration of soil gas Rn and CO2 considerably varies in the northern segment of the LPSFZ and is relatively stable in the southern segment. The spatial distribution of the concentration intensity and flux is strong in the north and weak in the south. However, the southern segment of the LPSFZ has a seismic gap that has not been ruptured by strong earthquakes with Ms ≥ 6.5 for the last 1400 years, whereas the seismic activity in the northern segment is relatively frequent, indicating that the fault zone locking degree of the southern segment is higher than that of the northern segment. This observation is completely consistent with the geochemical characteristic distribution of soil gas. Therefore, the southern segment of the LPSFZ should be considered a hazardous segment, where major or strong earthquakes can occur in the future.

Spatial variations of Rn and CO2 emissions in the Wuzhong–Lingwu region, northwest China

“…The frequency of seismic activity has been significantly lower than that in the west of Lingwu since 1970. Studies of low gas anomalies in some active fault zones indicated that the high locking degree of the fault constrains the migration of soil gas, whereas the creeping fault with a low locking degree is more favorable for the discharge of gas from deeper layers up toward the surface (Yang et al, 2018;Zhou et al, 2020;Yang et al, 2021). Although gas concentrations are low in the southern segment of the YRF, according to the slip rate inversed by InSAR, there is ~6.8 km locking in the southern segment of the YRF (Zhang et al, 2020), which the risk of strong earthquakes has increased.…”

Analisa Karakteristik dan Optimasi Sensor Gas TGS-2201 yang Direkomendasikan sebagai Instrumen Penginderaan pada Sistem Peringatan Dini Gas Beracun

“…Pada konsentrasi tinggi diatas ambang batas aman, gas beracun yang terhirup manusia dan/atau hewan dapat menyebabkan pingsan, kesulitan bernapas, dan detak jantung yang meningkat, pada kondisi paling parah, bahkan dapat menyebabkan kematian. Dalam pengukuran konsentrasi gas, dan menentukan ambang batas aman paparan gas beracun pada makuk hidup, dinyatakan dalam satuan Part per Milion (PPM), yang mana merupakan perbandingan massa jenis gas per satujuta bagian dari udara ambient [12] [13] [14]. Pada emisi gas beracun yang dihasilkan oleh aktivitas gunung berapi, dapat bervariasi jenis dan konsentrasi gas yang dihasilkan tergantung dari aktifitas magma dan komposisi batuan yang ada pada kawah aktif gunung api.…”