Spatial Variation of b-Values and Their Relationship with the Fault Blocks in the Western Part of the Tibetan Plateau and Its Surrounding Areas

Abstract

The Tibetan Plateau is considered to be one of the best natural laboratories for seismological research. This study sought to determine the spatial variations of b-values in the western part of the Tibetan Plateau, along with its surrounding areas, and the relation with the region’s fault blocks. The study region lies within 27–36.5° N, 78–89° E, and its fracture structure consists of strike-slip faults, as well as normal and thrust faults. A catalog record from 2009–2019 provided 4431 well-centered earthquakes that varied in magnitude from 0.1 to 8.2 M. The record was obtained from China’s seismological network, which is capable of recording low magnitudes to analyze b-values in the study area. The key findings of this study are as follows: (1) the range of earthquake depth in the region was 0–256 km, with the depth histogram showing a high frequency occurrence of shallow earthquakes in the area; (2) a time histogram showed that the major earthquakes occurred between 2014–2015, including the notable 2015 Gorkha earthquake (M = 8.2); (3) the b-value computed in the study area was 0.5 to 1.6, but in most of the study area, the b-value ranged from 0.6 to 0.9, which was a low to intermediate value, due to the presence of strike-slip faults in the central part of the study area and underthrusting in the region (south of the study area); and (4) a high b-value was found in the northwestern and eastern regions of the area, which proved that the area is prone to small earthquakes in the near future. The study also showed that the central and southern areas of the study region had low to intermediate b-values, meaning that it is prone to destructive and massive earthquakes with high magnitudes, such as the Gorkha earthquake (southern part of the study area). Low b-values revealed the degree of variation in rock properties, including large stress and strain, a fractured medium, a high deformation rate, and large faults. Small b-values were observed when the stress level was high in the investigated region, which might be used to predict a massive high-magnitude earthquake in the near future.

The Rise, Peak and Decline of the Seismic Hazard Related to Hydraulic Fracturing Activities in the Duvernay Play, Fox Creek Area, Alberta

“…Multiple studies (Fekadu & Kulhanek, 1994; Hussain et al., 2020) have observed significant spatial variations in the $$b$$‐value, even in proximal regions, resulting in areas with lower $$b$$‐values and higher seismic hazard and other areas with higher $$b$$‐values and lower seismic hazard. This is one of the key observations in the present study, where there is a large difference in seismic hazard between the Eastern and Western sections of the seismic cluster in Fox Creek due to the large difference in their $$b$$‐values (Figure 4).…”

GEOSTAT application design for rapid determination of MATLAB-based earthquake risk level

“…Several studies that will be tested using The GEOSTAT Application can be seen below: 1. Spatial Variation of b-Values and Their Relationship with the Fault Blocks in the Western Part of the Tibetan Plateau and Its Surrounding Areas [4].…”

ESTIMASI PARAMETER a-VALUE DAN b-VALUE UNTUK ANALISIS STUDI SEISMISITAS DAN POTENSI BAHAYA BENCANA GEMPA TEKTONIK DI WILAYAH MALUKU UTARA

“…Gambar 7 semakin memperkuat diskripsi Gambar 6, di mana gempa relatif besar akan terjadi di wilayah yang mengalami b-value drop besar (Prasad and Singh, 2015). Wilayah yang berwarna biru tua (wilayah dengan b-value drop besar) menunjukkan bahwa akumulasi energi seismik yang disimpan oleh batuan bawah permukaan relatif tinggi (Cao and Gao, 2002;Wu et al, 2018;Hussain et al, 2020). Hal ini berarti potensi gempa besar adalah relatif tinggi (Nuannin et al, 2005;Prasad and Singh, 2015).…”

“…Menurut kedua pola sebaran warna pada Gambar 8 dan Gambar 7, wilayah dengan b-value drop besar telah menahan stres yang relatif lama dan menyimpan energi potensial elastik dalam jumlah besar yang akan dilepaskan secara alamiah melalui mekanisme gempa besar. Oleh karena itu, wilayah b-value drop besar memiliki level seismisitas cenderung lebih rendah (Hussain et al, 2020) dibanding wilayah lain. Variasi spasial a-value di wilayah Maluku Utara memiliki rentang 7 ≤ 𝑎 ≤ 16 (spatially-averaged a-value = 11,5).…”