Innovation in Disaster Risk Reduction Applyng Global Investigations on La Molina Effects
INNOVATION IN DISASTER RISK REDUCTION APPLYNG GLOBAL INVESTIGATIONS ON LA MOLINA EFFECTS Julio Kuroiwa(1) SUMMARY Disaster Risk Reduction (DRR) globally has mainly been based on reducing the vulnerability of buildings and infrastructures, designing and constructing them more robustly, using, for example, seismic codes of Japan and California, USA, from the 1980s, which have substantially reduced structural damages. However, disaster reduction has lately evolved to disaster risk reduction. By adding risk, it is explicitly including the other risk parameter: hazard. In La Molina, during the Lima 1940, 1966 and 1974 earthquakes, the seismic intensities there were IX MMI while in most of Lima’s built up areas, the intensities were V-VI MMI. The borders of La Molina and Lima areas are separated by only a few hundred meters, but there were large differences in intensity. Those events are named microzonation effects. Inspired in La Molina microzonation effects, from 1966 to 2017, the author carried out field damage survey investigations of 25 important disasters occurred in the Americas, Japan and China, and a few more in Peru of geological and hydrometeorogical origin disasters, including climate change. The two most clear microzonation effects –of the globally investigated disasters– occurred: (1) during the 1985 Michoacan Mexico earthquake, Mw 8.1 USGS, when the peak acceleration was 12cm/s2, at Lazaro Cardenas Port, on stiff soil, close to the seismic epicenter, while in Mexico City (MXC), 350 km from the epicenter, the peak acceleration was 120 cm/s2 on muddy soil at the location of the old Texcoco Lake. The soil amplification was 10 times, in spite of the great distance of MXC from the seismic epicenter.
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