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This research work is inspired by the recently accepted concept that high frequency Rayleigh waves are generated in the epicentral zone of shallow earthquakes. Such high frequency Rayleigh waves with large amplitude may develop much of spatial variability in ground motion which in turn may cause unexpected damage to long-span structures like bridges, underground pipelines, dams, etc., in the hilly regions. Further, it has been reported that topography acts as an insulator for the Rayleigh waves (Ma et al. BSSA 97:2066–2079, 2007). The above mentioned scientific developments stimulated to quantify the role of shape and number of ridges and valleys falling in the path of Rayleigh wave in the insulating effect of topography on the Rayleigh waves. The simulated results reveals very large amplification of the horizontal component of Rayleigh wave near the top of a triangular ridge which may cause intensive landslides under favorable condition. The computed snapshots of the wave-field of Rayleigh wave reveals that the interaction of Rayleigh wave with the topography causes reflection, splitting, and diffraction of Rayleigh wave in the form of body waves which in turn provides the insulating capacity to the topography. Insulating effects of single valley is more than that of single ridge. Further this effect was more in case of elliptical ridge/valley than triangular ridge/valley. The insulating effect of topography was proportional to the frequency of Rayleigh wave and the number of ridges and valleys in the string. The obtained level of insulation effects of topography on the Rayleigh wave (energy of Rayleigh wave reduced to less than 4% after crossing a topography of span 4.5 km) calls for the consideration of role of hills and valleys in seismic hazard prediction, particularly in case of shallow earthquakes.

Vulnerability assessment of 36% healthcare facilities in the province of Uttarakhand that has high probability of witnessing a large magnitude earthquake in near future reveals 67.02% to be put to disuse immediately after an earthquake. Healthcare facilities in Pithoragarh, Haridwar, Almora, Tehri Garhwal, Champawat and Nainital districts are observed to be particularly vulnerable and this is to make mobilisation of medical response a major challenge and result in escalated loss of human lives, enhanced trauma of the earthquake affected population and consequent civil discontent. The earthquake is estimated to cause economic loss of US$ 37.06 million to the surveyed health infrastructure alone. An investment of US$ 17.94 million is assessed as being required for ensuring seismic resilience in the surveyed health infrastructure which in turn is estimated to save critical medical instruments and facilities worth US$ 19.12 million that would otherwise be lost under collapsing buildings. Having identified non-compliance of building codes, poor quality of construction and lack of maintenance as being the factors enhancing vulnerability of healthcare infrastructure it is recommended to undertake measures for (i) prioritised demolition and reconstruction of Grade 5 buildings, (ii) detailed assessment and phased retrofitting of Grade 4 and Grade 3 buildings, (iii) effective and strict compliance of building bye-laws, (iv) stringent punitive measures for life threatening lapses in public buildings, (v) mechanism for routine vulnerability assessment and corrective maintenance of public buildings, and (vi) making disaster safety a precondition for operating any healthcare facility and linking it to their licensing.