Moho offsets beneath the Western Ghat and the contact of Archean crusts of Dharwar Craton, India

Lateral Variations of Moho Depth and Average Crustal Properties Across the Taiwan Orogen From H‐V Stacking of P and S Receiver Functions

“…As illustrated in Figure 3, the backazimuth‐wise stacked P RFs for several stations located near the geologic structural boundaries reveal clear sinusoidal or step variations in the Ps arrival times. Such variations have been deliberated in many RF studies (e.g., Liu & Niu, 2012; Schulte‐Pelkum & Mahan, 2014; Shiomi & Park, 2008) as an indication of the presence of crustal anisotropy and/or the steeply dipping/vertical offset of the Moho (Saikia et al., 2016; Schulte‐Pelkum et al., 2005; Shi et al., 2009). Through simple harmonic decomposition of Ps ‐ P times as a function of backazimuth shown in Figure , those observed at CHGB sitting next to the western boundary of the CR and TWKB in southernmost Taiwan exhibit sinusoidal quasi‐periodic variations which have both components of 2π and π periodicity associated with dipping Moho and crustal anisotropy, respectively.…”

“…In reality, the observed RFs often vary significantly with backazimuth mainly due to the complexity of the nonplanar Moho geometry and crustal velocity structures. In addition, the presence of low-velocity sediments, intra-crustal layers, a gradational crust-mantle transition, and a dipping or offset Moho can also produce ambiguous H-κ results (Saikia et al, 2016;Yu et al, 2015). Some of these drawbacks may be improved by incorporating the S RFs in the analysis since the Moho Sp conversion and its crustal multiples are unambiguously separated by direct S. Likewise, the equations for arrival times of these phases relative to S, t Sp , t SsPp , and t SsSp are given by…”

Bulk Crustal Properties and Layered Velocity Structure in Fujian, SE China: Constraints From P and S Receiver Functions

“…The crust-mantle boundary or the Moho is in general known as one of the most significant discontinuity featuring highamplitude converted and reverberated phases in P RFs. The above equations have been widely used to evaluate the crustal thickness (H) and V p /V s ratio or κ by means of the H-κ stacking technique of Zhu and Kanamori (2000), which performs a grid search for the optimal H and V p /V s ratio, given a priori assumed constant Vp of the crust, to reach the maximum value of a function defined as the weighted sum of amplitudes of the Moho related phases marked at the corresponding predicted arrival times relative to direct P. In reality, the Moho discontinuity can be inclined or nonplanar and behave as a gradual velocity transition (Endrun et al, 2005;Tang et al, 2011;Saikia et al, 2016). Moreover, the continental crust is usually multi-layered and anisotropic and may consist of a thick, low-velocity sedimentary cover on the top (Schulte-Pelkum and Mahan, 2014; Yu et al, 2015).…”

A review of seismological research in India during the past five years (2015-2019)

“…This section discusses the crustal thickness/ composition and the nature of crust-mantle boundary beneath Southern India encompassing the Dharwar craton, southern granulite terrain, Proterozoic basins, rifted margins, escarpments and the DVP. The crustal image along an east-west profile starting from the west coast to east coast (south India), cutting across the major geological features like the escarpment, WDC and EDC reveals that the Moho depth varies from 34 to 41 km with a sharp offset of ~8 km at the boundaries or contact zones between the Western Ghats and WDC; WDC and EDC (Saikia et al, 2016). While the offset in the Western Ghats is attributed to its differential uplift during the India-Madagascar separation, the one at the contact between WDC and EDC is ascribed to the presence of a steeply dipping fault that separates them.…”