WORLD AGENCY OF PLANETARY MONITORING AND EARTHQUAKE RISK REDUCTION

QUAKELOSS

A COMPUTER TOOL TO ESTIMATE BUILDING DAMAGE AND HUMAN LOSSES DUE TO EARTHQUAKES ANYWHERE IN THE WORLD

The input needed for a loss calculation is the earthquake origin time, the coordinates of the epicenter, the depth and the magnitude. The program then calculates the ground shaking as a function of distance from the epicenter. In the data base of QUAKELOSS the population of about 2 million settlements is known and each settlement has a profile of building fragility. The degree of damage due to the calculated shaking is determined for each of five fragility classes, and from that the resulting numbers of fatalities and injured are estimated.

The most accurate results could be obtained if the building inventory had been compiled by engineers on the ground. However, this is not possible for most cities, especially in developing countries. For this reason, the building fragilities have been calibrated, using about 1000 earthquakes for which losses are known. Therefore, QUAKELOSS estimates are most reliable in countries where earthquakes occur frequently. The building stock in countries without recent earthquakes is extrapolated from neighboring areas with similar building style and quality.

For EVALUATION of the performance of QUAKELOSS, we calculated losses for more than 500 earthquakes, independently from the program's developers and found satisfactory to good performance.

The true test of the performance is provided by REAL-TIME ESTIMATES because no adjusting of parameters is possible to achieve the correct results. The real-time estimates are usually distributed approximately 2 hours after an earthquake occurs. They can assist rescue teams to make a decision whether or not to mobilize. The table in the above link is updated in near real-time.

The output of QUAKELOSS consists of an estimated range of numbers of fatalities and one of injured, a map showing the expected average degree of damage in the settlements affected. If needed a list of settlements can be supplied with the expected numbers of fatalities and injures, as well as the percentage of buildings expected to fall into each of 5 classes of destruction. An example of a map showing the degree of destruction in settlements is shown for the EARTHQUAKE OF THE MONTH.

Loss estimates can also be made for scenario earthquakes. That means, earthquakes that are likely to occur in the future. The parameters of scenario earthquakes have to be estimated by expert opinion. The location could be selected in a segment of a plate boundary that has not ruptured recently, but where an earthquake rupture happened nearby not long ago, a seismic gap. The magnitude can be derived from the length of the gap, or by selecting the mean magnitude of the historic large earthquakes in the vicinity. An example for LOSSES DUE TO A SCENARIO EARTHQUAKE is shown for the Himalaya.