Hardly a week passes without our learning of natural geologic disaster
somewhere in the world, be it a volcanic eruption, landslide, or
destructive earthquake. The prominent public notice given to such events
is not only the result of better communications, but also results from
the increased impact of these events on a growing human population. In
recent years, the population has increased greatly in regions of active
tectonics. Northern India and the surrounding areas are prime examples.
The consequence is that people and their man-made structures are
concentrated close to active faults and steep, landslide-prone terrains.
In just the past several years, even moderate earthquakes with seismic
magnitudes less than 6. 5 have killed as many as 20,000 people precisely
because these earthquakes occurred directly beneath population centres
in central India. The greater Himalayan region, including the Ganges
Plain, is a prime example of the coexistence of a pronounced geological
hazard with a growing human population. Due in part to the spectacular
topography, the region has long attracted scientific investigations, and
may be considered as the birthplace of modern studies of earthquake
hazards. R. D. Oldham (1858-1936) of the Geological Survey of India
played a prominent role in the development of modern studies of
historical seismicity, active faulting and seismic wave analysis. Oldham
published extensively on the earthquakes and the geology of India,
including his report entitled "Catalogue of Indian earthquakes from the
earliest time to the end of A. D. 1869" (Mem. Geol. Surv.
