**2. Methodology**

The Bhuj earthquake (2001), had caused severe damage to property and more than 20,000 people were killed in Kuchchh area [1]. The reported PGA of the earthquake was 0.38 g having magnitude 7.7 Mw. Around 70 multistorey buildings collapsed in Ahmedabad, with reported PGA of 0.1 g for which the damage observed was higher than expected. Hence, the influence of present process of design of buildings on the performance of RC structures needs further check. There is another significant parameter for design consideration - the accurate hazard estimation. The observed damages better indicate hazard than the PGA values especially for mid-high rise buildings. The attenuation in Ahmedabad city is found to be around 1.8–2.0 [2], not considered in design. This is the serious limitation of force-based design wherein inaccurate estimate of hazard will give a sense of design

to the engineer but is a gross-error in seismic design force calculations.

*Natural Hazards - Impacts, Adjustments and Resilience*

Ahmedabad gives understanding of hazard to design engineers.

estimation (refer Eq. (1)).

**Table 1.**

**212**

The expression of risk gives a good overview of each part that contributes to either the safety or to the weakness. In the equation, the term Hazard (H) represents the severity of earthquake expected in the region considered for risk

Risk ¼ Hazard Hð Þ� Vulnerability Vð Þ� Exposure Eð Þ*=*Asset (1)

If the estimation of hazard is an under-estimate, then the risk increases substantially, though the design may be done with utmost care. Seismic micro-zonation of

The building typology and design methods followed in a region suggest vulnerability aspects. Without disturbing the cultural heritage of local region, the capacity of existing buildings can be increased to reduce the quantum of vulnerable stock to various intensities of earthquake likely to hit there [3]. The role of developer, owner and administration plays a vital role in upgradation of vulnerable facilities and investing efforts towards the mitigation of earthquake hazard by identifying the vulnerability (V) component in a region. The density of buildings in an area, important structures, and the type of facility under threat is covered by the risk as the exposure or asset (E) parameter to estimate the threat susceptibility. The impact of earthquakes in India show the concern due to recent earthquakes (2001;2005) on

the number of people succumbed due to lesser engineering (refer **Table 1**).

focuses on adopting resilience in mid-rise buildings using design tools.

*List of severe earthquakes in India (7 Mw): Magnitude-PGA-intensity.*

Hence, if we are better able to know our region, dedicated in identifying weak structures for upgradation and protect the important assets by identifying their importance, we can control the impact of earthquakes on our habitat. This study

**Event Year Magnitude PGA Intensity Casualty** India-Burma 1988 7.2 0.34 g VIII 709 Garhwal 1991 7.1 0.3 g VIII 768 Uttarkashi 1991 7 0.29 g IX >2000 Koyna 1967 6.5 0.4 g VIII 1500 Chamoli 1999 6.6 0.34 g VIII 103 Bhuj 2001 7.7 0.38 g VIII 20,000 Kashmir 2005 7.6 0.23 g VIII >80,000 Sikkim 2011 6.9 0.35 g VI 111 Nepal 2015 7.9 — IX >8000
