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. (2) The other case occurred in Tambo de Mora, some 15 km north of Pisco, during the 2007 Ica Region Peru earthquake, Mw 8.0 USGS. In the multihazard map (MHM) developed in 2001-2002, under the frame of the Sustainable City Programme INDECI/UNDP 1998-2015, the city’s lower sector was classified as being of very high/high hazard, and a small area resulted from cutting a rigid hill, where a church and deposit were built with 4.2 m and 2.6 m very vulnerable adobe walls respectively, but they did not suffer any damage as was classified six years before with low hazard. In spite of the fact that Tambo de Mora was located on top of the interacting Nazca and South American plates that had coseismic displacements. At the lower part of Tambo de Mora the seismic intensity was IX MMI and generalized soil liquefaction occurred. The destruction of buildings and infrastructures there was total, whereas no damage was observed in those two adobe constructions. The intensity there was V MMI, i.e. four degrees of difference in the seismic intensity. These two examples show how important it is to consider hazard in DRR, using peak acceleration or seismic intensity, the two indicators most used in engineering practice. In cases of hydrometereological and climate change disasters, the site topography is usually more important than the other site characteristics, as happened in New Orleans, during the 1995 Katrina hurricane, since 80% of the city was below the water level of the river and lake surrounding the city during the event. The other case was Sullana, Peru, where La Quebrada, the lower strip of an open “V”-shaped valley, was destroyed when the Pan-American highway with a 4.0 m high platform, which dammed a large volume of water during El Niño 1982-83, collapsed, destroying a width of three to four blocks of the bottom of La Quebrada, along its full length up to where it flows into the River Chira. This is an effort to let decision makers and practicing professionals involved in investment know that it is possible to substantially reduce human and material losses by expanding and densifying cities, locating hospitals, schools, key components of water services and business investment sites of new buildings and infrastructures in areas of very low and low hazards; and by investing in identifying the best location and making detailed investigation of all aspects that permit hazard reduction, and applying updated technologies to reduce the vulnerability of constructions. But above all, it is necessary to invest in good scientific technical education, so that DRR can become usual professional practice. The answer to the other two action plan priorities of Sendai Frame 2015-2030 has been provided by updating to 2018, the author’s 2005 book Disaster Reduction now entitled Disaster Risk Reduction in the 21st Century. There, government officials and broad spectra of practice professionals, may find guidance on how to strengthen governance and how to rebuild better – and where. Keywords: Disaster reduction, disaster risk reduction, microzonation effects, geologic and meteorological disasters, action plan priorities, knowledge on disasters, rational investment. (1) Professor emeritus National University of Engineering. Lima, Peru. Director general manager Disaster Risk Reduction Peru International SAC. E-mail: [email protected]. UNISDR Making Cities Resilient: My City is Getting Ready. Member of Advisory Panel 2010-2015. 1 1. OVERVIEW AS AN INTRODUCTION The global tendency to reduce losses in buildings and infrastructures during disasters was to build them more robustly, focusing on reducing their vulnerability. For example, buildings designed in California, USA, and in Japan applying seismic codes from the 1980s have substantially reduced the structural damage. However, non- structural damage and buildings’ contents (NSDBC) has accounted for a high percentage of earthquake material losses during the last two decades, as occurred during the earthquakes of 1994 Northridge, CA, USA; Kobe 1995 and Tohoku 2011, Japan; as well as in the Maule, Chile, 2010 event. For example, in Kobe 1995, structural damage in hospitals was only 8% of the total losses, and 92% was losses in NSDBC. This is understandable, bearing in mind the high cost of the delicate electronic medical equipment and its vulnerability to impact on hard floors. The Santiago de Chile International Airport was out of service for about a month due to large NSDBC damages. In both cases the seismic intensity was very high, due to local unfavorable soil characteristics. According to the Sendai Frame for Disaster Risk Reduction (DRR) 2015-2030, the first priority is to understand DRR, and the third to invest in DRR for resilience. To reduce NSDCB damage, it is necessary to know that in those cases losses were caused by excessive lateral flexibility of the buildings, which may be reduced by adding rigid shear walls symmetric in plan, with no rigidity change in elevation, thus reducing lateral drift uniformly. For example, to less than 0.007 for reinforced concrete buildings as regulated by the Peruvian Seismic Code since its 1997 version to the present (2016). Excessive lateral flexibility also caused severe damage in reinforced concrete buildings during the 2016 Ecuador earthquake, when hospitals, including one under construction, were totally lost in the macroseismic area. It may be clearly noted in the pictures of the damaged reinforced concrete buildings caused by the 2017 Iran/Irak earthquake, that the filling brick walls inside the RC columns and beams were destroyed because there was no control of the lateral drift. So it is necessary to invest in efficient architectural and structural engineering education, in such a way that reducing NSDBC and eliminating other known structural defects will become routine professional practice. In this respect, international cooperation is effective. JICA, in March 2018, donated a shaking table mounted on a truck to CISMID/UNI Lima-Peru, through Peru’s Civil Defense, to demonstrate how strong earthquakes are felt inside a room. For sure, contents, furniture, and frames hanging on the walls will fall down when the equivalent intensity reaches VII to VIII MMI. The problem will not be solved only professionally, but also directly by home owners: observing this demonstration, they can learn that it is mainly their problem. The cost of small pieces of steel for fixing a building’s contents is not an economic problem, but it is necessary for the owner to be aware of the risk, and how to reduce it, so that he can then to take steps to ensure the personal protection of his family and to reduce material losses. Lately – globally -- disaster reduction has evolved to disaster risk reduction. By adding risk, the term explicitly includes its other component: hazard. The field damage investigations of 25 important disasters ocurred in the Americas, Japan and China, as well as some more with microzonation effects in Peru, were investigated by the author from 1966 to 2017, focusing on the strong influence of the site characteristics of soil and topography in hazards of geological and hydrometeorological origin, including climate change. The field damage investigations included earthquakes that occurred in California USA in 1971, 1989 and 1944, in Chile 1985 and 2010, Caracas Venezuela in 1967, Mexico 1985, and Peru 1966, 1970, 1974, 1979, 2001 and 2007; other events included were in Japan 1995 and 2010 and China in 2008, Hurricane Katrina 2005 and Andrew 1992, in the USA and Mitch 1990 in Central America, the volcanic eruption of Monte del Ruiz Colombia 1985, and the El Niño 1992-83, 1997-98 and 2017 in Peru and Ecuador. In the early years, my being in the field from 10 days to about two weeks at a time was possible thanks to the generosity of different individuals and institutions. For example, late Caltech professor emeritus George W. Housner, using funds of USNSF, made it possible for me to be in Caracas and the Venezuelan Caribbean coast for more than two weeks, reviewing the architectural and structural building projects, inspecting damage, and interchanging ideas with local practicing engineers and university professors.