abstract
The transition boundary zones of colliding crustal plates are sites of significant lateral inhomogeneities. A layered model with lateral inhomogeneity (following an exponential law) is constructed for the Himalayan region where, according to plate theory, a mobile continent collides with a relatively stationary crustal block. The Love-wave dispersion characteristics of such a model are evaluated by raytheory techniques. Analysis of Delhi data of the Severnaya Zemlya earthquake of August 25, 1964 results in estimates of the values of velocity, rigidity and density gradient as 1.14 × 10−3 sec−1, 0.42 × 10−3 gm cm−3 km−1 and 2.85 × 10−3 dynes cm−2 km−1, respectively. The corresponding crustal thickness experienced by the Love waves in the Himalayan region is calculated as 50 km. Validity of the model and tectonic implications of results are discussed, along with interpretations of other seismic studies of the region.
