By linking economic losses with human losses to create a PAGER alert, is the USGS putting a value on human life?
No. The economic loss and casualty estimations are independent of each other. If the loss of life is expected to exceed 100, then an orange alert is assigned for loss of life, no matter what the economic loss is estimated.The two alerts are then compared, and the higher is always chosen.Thus, for example, if there is a green alert for loss of life, but an orange alert for economic losses, then an overall orange alert is issued. The same for if an orange alert is estimated for loss of life, but a green alert is assigned for economic losses,the overall alert would be orange. The system is by no means suggesting that 1,000 lives are equal to $1 billion. Those are simply the numbers chosen for the triggers due to past experiences for response.
This system is designed to help relief organizations and response agencies determine the likely impacts of the earthquake as soon after the event as possible. The colored alert system does not rank the earthquake in importance; it simply indicates the estimated economic and human losses of the earthquake in the crucial, initial hours after an event, in order to better prepare responders.
The ratio of fatalities to economic losses will be higher in developing countries, particularly those with building inventories that are highly vulnerable to earthquake shaking, than in countries that have a high percentage of earthquake-resistant buildings.