Simplifications Earthquake casualty estimation

1 simplifications

1.1 averaging
1.2 models settlements
1.3 expected mortality city district

simplifications

simplifications needed because world large details everywhere.

averaging

if 1 wanted estimate in real time damage expected critical facilities (e.g. nuclear power plant, high dam of reservoir, bridges, hospitals, schools) 1 have know quite few additional details. example, type of soil facility resting on, blueprints of construction calculate response different frequency waves, , frequency spectrum radiated earthquake. can done, costly. in developing countries, not of information available.

in estimating losses in real time, 1 must take advantage of fact buildings built code, others not, located on hard rock, others on unconsolidated sediments, , earthquake may radiate more energy in 1 direction in another. summing expected losses assuming average conditions may end approximately correct, although local fluctuations in results exist.

models settlements

figure 6: photograph space showing neighborhoods of relatively homogeneous building stock can defined, , industrial buildings can distinguished residential ones. (source: wapmerr, geneva, www.wapmerr.org).



figure 7: using shadows cast buildings, 3d model of built environment of bucharest has been constructed. percentages of buildings in height classes can derived city , districts (district limits marked red lines). information helps define distribution of buildings classes of vulnerability strong shaking, if basic engineering information on construction types present available street surveys. (source: wapmerr, geneva, www.wapmerr.org).

photographs taken space or air planes useful assembling database built environment of city. on images have not been enhanced size , type of buildings, building use can identified (figure 6). neighborhoods of residential buildings of similar construction, , industrial zones can mapped.

the height of buildings can estimated shadows cast in photographs space , air. based on height, estimates 3d models of cities can constructed, shown in example of central bucharest (figure 7). governmental office buildings can seen @ center, whereas small residential buildings dominate in east.

adding photographs of facades shot street level, detailed, realistic models of cities can built (figure 8). added information, possible better classify construction type of each building , deepen detail of model of built environment necessary accurate estimates of losses due earthquakes.

however, number of settlements in world population data available exceeds 1 million. each, coordinates, name, , estimated population available, impossible analyze of them in detail shown in figures 6, 7, , 8. there no choice, place entire population @ 1 coordinate point, regardless of settlement’s size, , assign each settlement standard distribution of buildings classes of different earthquake resistance. refinement 1 can afford have different standard models different countries , @ least 3 settlement size each country.

in ideal case, 1 have detailed information on every building , occupants. however, thousands of large cities @ risk , hundreds of millions of inhabitants in them, costly. cost-effective way model large city treat each administrative district separate settlement.

expected mortality city district

in many large cities, census contains information on population , building stock district. model of city in each district has own distribution of buildings classes , population, far superior basic, primitive model of 1 coordinate point. if 1 has resources divide large city neighborhoods containing similar building stock, high quality model can constructed @ still moderate cost. example of mortality rate estimates in case of future m8 earthquake off lima, peru, shows there substantial differences between districts (figure 9). differences due distance assumed source, type of soil, , quality of building stock. in addition mortality calculation entire population, information on locations , expected damage state of schools, hospitals, fire stations, police posts, , critical facilities of great value rescuers. however, develop type of information requires more substantial effort in countries location , construction quality of these facilities not known.

calculating functionality of hospitals after earthquakes requires specialized expertise. in cities, elaborate efforts commercial enterprises have been carried out or under way catalog information on neighborhood level, more detailed shown in figure 9. in industrial countries details of each house street address known.