With the greatest pleasure, we present the second special issue of the Journal of Disaster Research (JDR), entitled Enhancement of Earthquake and Tsunami Disaster Mitigation Technology in Peru. This follows the first special issue on the same theme. These special issues contain 36 articles, 15 in the first and 21 in the second. They summarize research output from the SATREPS Peru project. SATREPS is an international research program sponsored by the Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA). As a SATREPS project on natural disaster mitigation, our 5-year Peru project began in March 2010 with the purpose of enhancing and implementing earthquake and tsunami disaster-mitigation technology in Peru.
The joint research project provides good opportunities for Peruvian and Japanese researchers and engineers to work together exchanging opinions on their common goal of reducing loss from earthquakes and tsunamis. Within the project period, CISMID was designated as a government agency in charge of disaster-mitigation activities. Project outcomes have been introduced in national design codes and in guidelines on earthquake and tsunami risk evaluation in Peru. Our project has drawn great attention among members of Peruvian society. It has attracted hundreds of participants and scores of mass media through public seminars and symposia. We expect the project to be sustained through public awareness and dissemination activities by Peruvian organizations.
We hope this special issue will provide useful information to seismic-prone Asia-Pacific countries, especially Latin America. In closing, we sincerely thank the contributors and reviewers who have done so much to make the articles in this special issue both interesting and valuable.
One of the SATREPS projects on earthquake and tsunami disaster mitigation technology in Peru has been promoted since March 2010 for a five-year period. The project focuses on five research fields, i.e., seismic motion and geotechnical, tsunamis, buildings, damage assessment, and disaster mitigation planning. Collaborative research has been carried out through joint experiments, observations, field surveys, computer simulations, seminars and workshops. With the Lima metropolitan area and the city of Tacna set as case study sites, two mega-thrust earthquakes have been simulated and their effects and countermeasures investigated. The simulation results have been validated by observation data and have been implemented in government policy. Young Peruvian engineers and scientists have also received training and education. This paper summarizes the progress and outcomes of the SATREPS project for earthquake and tsunami disaster mitigation in Peru.
We estimate several scenarios for source models of megathrust earthquakes likely to occur on the Nazca-South American plates interface in southern Peru. To do so, we use a methodology for estimating the slip distribution of megathrust earthquakes based on an interseismic coupling (ISC) distribution model in subduction margins and on information about historical earthquakes. The slip model obtained from geodetic data represents large-scale features of asperities within the megathrust that are appropriate for simulating long-period waves and tsunami modelling. To simulate broadband frequency strong ground motions, we add small scale heterogeneities to the geodetic slip by using spatially correlated random noise distributions. Using these slip models and assuming several hypocenter locations, we calculate a set of strong ground motions for southern Peru and incorporate site effects obtained from microtremors array surveys in Tacna, the southernmost city in Peru.
Microtremor exploration was performed around seismic recording stations at five sites in Lima city, Peru in order to know the site amplification at these sites. The Spatial Autocorrelation (SPAC) method was applied to determine the observed phase velocity dispersion curve, which was subsequently inverted in order to estimate the 1-D S-wave velocity structure. From these results, the theoretical amplification factor was calculated to evaluate the site effect at each site. S-wave velocity profiles at alluvial gravel sites have S-wave velocities ranging from ∼500 to ∼1500 m/s which gradually increase with depth, while Vs profiles at sites located on fine alluvial material such as sand and silt have S-wave velocities that vary between ∼200 and ∼500 m/s. The site responses of all Vs profiles show relatively high amplification levels at frequencies larger than 3 Hz. The average transfer function was calculated to make a comparison with values within the existing amplification map of Lima city. These calculations agreed with the proposed site amplification ranges.
The location of Lima city and El Callao in the Pacific coast and the long history of seismic activity were the main reasons to develop a seismic microzoning map. The microzoning study was based on large numbers of geotechnical and geophysical exploration points distributed around the study area. The geotechnical exploration consisted of borehole tests and pits, from which soil samples were taken to the laboratory to determine the soil mechanical characteristics. The geophysical exploration consisted of one-point microtremor measurements and various methods to estimate the S-wave velocity profile. The results of both, the geotechnical and geophysical exploration were combined to develop a seismic microzoning map for Lima city and El Callao. This map shows five zones, where the zone with the best soil mechanical and dynamic characteristics covers most of the study area.
A currently populated slope in the northeast part of the city of Lima was selected as the target area of this study, with the aim of analyzing the influence of topography on its seismic response. A finite element model was constructed using soil information obtained by microtremor array measurements conducted in flat and sloping areas, and solved for plain strain conditions in the time domain using an input motion developed for the most critical slip model of a simulation for megathrust earthquakes. Results showed that for this typical rocky slope, topographic effects do not have a significant influence on its seismic response, except for areas close to the foot of the slope where, even if soil vibration is restricted, an amplification of the seismic motion is still expected for short period structures.
An earthquake shook the central-southern coast of Peru on August 15, 2007, as a coseismic effect a tsunami was generated, which flooded some villages and beach resorts and killed 3 people. From the analysis and signal processing of 10 tidal records, we obtained the parameters of the seismic source and the initial coseismic deformation through an inversion modeling, in which the synthetic signals are compared with the observed signals by a non-negative least square method. The maximum slip located on the southern part of the rupture geometry is 7.0 m. The calculated scalar seismic moment is M0=1.99×1021 Nm, equivalent to a magnitude of Mw8.1. We used these parameters to obtain a heterogeneous seismic source model, which was used as initial condition to simulate the tsunami propagation and inundation. We used the field survey observations to validate our source model.
We estimated, from twelve scenarios of potential megathrust earthquakes, the tsunami impact on the Lima-Callao region in Central Peru. In addition, we conducted hazard mapping using the local envelope of the maximum inundation simulated in these scenarios. The deterministic approach is supported by the decades of geodetic measurements in this area that characterize the interseismic strain build up since historical megathrust earthquakes. The earthquake scenarios for simulation proposed in  introduce spatially correlated short-wavelength slip heterogeneities to a first slip model in  calculated from the interseismic coupling (ISC) distribution in Central Peru. The ISC was derived from GPS monitoring data as well as from historical earthquake information. The results of strong ground motion simulations in  reported that the slip scenario with the deepest average peak values along the strike (Mw=8.86) generates the largest PGA in the Lima-Callao area. In this study, we found from tsunami simulation results that the slip model with the largest peak slip at a shallow depth (Mw=8.87) yielded the highest tsunami inundation. Such differences in maximum scenarios for peak ground acceleration and tsunami height reveal the importance of a comprehensive assessment of earthquake and tsunami hazards in order to provide plausible worst-case scenarios for disaster risk management and education.
The implementation of adequate urban development and measures systems against tsunami impact in coastal communities is improved by understanding damage probability among building structures. Within the framework of the project Enhancement of Earthquake and Tsunami Disaster Mitigation Technology in Peru (JST-JICA SATREPS), the authors analyze the damage probability of building structures due to tsunami impact in the Callao region of Peru. Two different tsunami hazard scenarios are assumed in assessing building damage probability. The first tsunami scenario represents the worse-case scenario of tsunami inundation that calculates the envelop of maximum inundation depth and flow velocity values from 12 probabilistic megathrust earthquake scenarios for central Peru. The second tsunami scenario corresponds to a historical tsunami event in this region. We apply a methodology for evaluating different levels of building damage by combining tsunami numerical results and tsunami fragility functions. Damage probability was analyzed in detail on a single building scale in the La Punta district. For the rest of Callao region, analysis was performed on a block-unit scale. Our results suggest that approximately 30% of submerged building may be washed away by tsunami inundation in the probabilistic hazard scenario and approximately 60% in the historical hazard scenario.
Damage to confined-masonry-brick or concrete-block house was assessed for being subjected to a tsunami wave load. This study was prompted by recent three tsunamis – one during 2001 on the Near Coast of Peru, one in 2009 in the Samoa Islands, and one in 2010 in Maule, Chile. We analyzed 13 damaged walls from 10 single-storey houses located near the coastline. We focused on evaluating the tsunami wave pressure distribution on house walls. Based on the formula proposed by Asakura et al. (2000) to evaluate tsunami wave pressure distribution on a structural component located on land behind on-shore structures, which is used for designing a tsunami evacuation building, we identify the values of horizontal wave pressure index a in Asakura’s formula for walls and discuss the boundary value of a at which a wall presents structural damage, such as in collapse and cracking failure modes.
The Japanese and Peruvian experimental databases on confined brick masonry walls are put together as one database, and the strength and deformation of the walls are reviewed. First, the applicability of existing equations for the ultimate strength of reinforced concrete or reinforced masonry walls to the estimation of the maximum strength of confined brick masonry walls which failed in shear, flexural-shear, or flexure when subjected to lateral forces, is discussed. Then, empirical equations for the maximum strength, displacement at maximum strength, and ultimate state of the walls are proposed based on multiple regression analysis, and the accuracy of the proposed equations is discussed. It is concluded that the maximum strength can be estimated using the existing equations or the proposed empirical equations with good accuracy. The deformations at maximum strength and the ultimate state can be estimated using the proposed empirical equations, although there is a large amount of scatter.
Confined masonry walls represent one of the most widely used construction systems for dwellings in Peru and other Latin countries. This study describes the procedure for implementing a database with a web interface of results collected from the experiments conducted over the years by the Japan Center for Earthquake Engineering and Disaster Mitigation. This paper attempts to contribute to the seismic design procedure of this type of structure, and parameters such as stiffness ratios and the deformation (drift) for the characteristic stages of confined masonry walls under different limit states or performance levels are proposed. Also, a semi-empirical equation for estimating the shear capacity using the database is proposed.
Under the Peru-Japan SATREPS Project, a building monitoring system has been implemented in Lima city, supported by JST and JICA. This network monitors three buildings (HERM, PC-UNI and FIC-UNI); each building has five sensors, which consist in a GMR accelerometers. These buildings have different characteristics, such as age, ground mechanic properties, structural systems, and structural status. Since the implementation of this network, some quakes have been recorded. This paper describes the implementation of the monitoring network, and presents the response of the target buildings and their dynamics characteristics during these quakes.
Reinforced concrete (RC) buildings in Peru use low ductility walls, with rectangular cross-sections and reinforced with wire mesh and vertical reinforcement bars at boundary ends, as structural elements. These structural elements have no columns, have small amounts of reinforcing bars and are expected to fail in a brittle manner. In this study, a performance verification test is conducted on the use of carbon fiber sheets (CFS) as a retrofitting method for shear walls without boundary columns. The focus is on retrofitting walls that fail in flexural mode. In other words, although an increase in strength cannot be expected, CFS retrofitting can delay the concrete crushing of the shear wall base that occurs during flexural failure; and the aim is to verify this improvement in deformation performance due to CFS retrofitting. From the test, by retrofitting the RC shear wall without boundary columns with CFS, it was found that post-maximum strength deterioration was more gradual, and deformation performance was improved. And Ultimate limit deformation of specimen which was partially retrofitted at the boundary ends of the wall was larger than that of specimen which was retrofitted over the entire wall span.
Masonry is one of the most common structural materials used to build houses in the city of Lima, Peru. The structural features of this material and its components vary widely, however, due to the manufacturing process, which uses bricks and aggregates and different levels of labor. This paper presents experimental results realized using bricks, prism and wallettes to determine the mechanical properties of masonry.
In Peru, the most commonly used structural system for housing construction is based on confined masonry walls. Solid engineered walls are regulated by the NTE-E070 standard, which lays down a required degree of earthquake resilience. However, around 60% of the population lives in non-engineered houses that use tubular blocks for their walls. This paper presents a comparison of the behaviors of non-engineered tubular block walls and solid engineered walls. Tests were performed on a tubular brick wall by subjecting it to horizontal cyclic loading to examine the effects under a constant axial load of 20 tf. Then, the test results were compared with those for walls in the CISMID Structural Lab database. The resistance of the tubular brick wall in terms of shear stress was found to be relatively low, having an average value of 4 kg/cm2, while the solid walls can withstand a shear stress in excess of 5.5 kg/cm2.
The actual behavior of thin RC wall high-rise buildings during an earthquake in Lima, Peru, and the associated seismic loss is unknown. This type of building was assessed done using analytical fragility functions. The numerical model was based on full-scale tests done in Lima, Peru. Nonlinear dynamic response analysis was performed using records simulated for Lima. The damage ratio was estimated for four damage states and fragility functions were obtained assuming that the damage ratio followed log-normal distributions. Seismic performance was evaluated by considering the probability of different damage states for three seismic hazard levels. It was found that high-rise buildings present a low probability of collapse in severe earthquakes.
Even though detailed building inventory data are necessary for estimating earthquake damage reliably, most developing countries do not have sufficient data for such estimations. This necessitates a way for finding building distribution and feature easily. In this study for estimating the number of households in all building categories of different structures or floor numbers in Lima, Peru, where a great earthquake is expected, we propose an estimation method based on existing GIS data from a census, satellite imagery, and building data from field surveys, and apply it to estimate the entire area of Lima for create building inventory data. Building fragility functions were used to calculate a severe damage ratio of buildings due to the expected earthquake. The rate was multiplied by created building inventory data to estimate the number of households in damaged buildings. Furthermore we clarified damage reduction by retrofitting for low earthquake-resistant buildings.
Building data, such as footprint and height, are important information for pre- and post-event damage assessments when natural disasters occur. However, these data are not easily available in many countries. Because of the remarkable improvements in radar sensors, high-resolution (HR) Synthetic Aperture Radar (SAR) images can provide detailed ground surface information. Thus, it is possible to observe a single building using HR SAR images. In this study, a new method is developed to detect building heights automatically from two-dimensional (2D) geographic information system (GIS) data and a single HR TerraSAR-X (TSX) intensity image. A building in a TSX image displays a layover from the actual position to the direction of the sensor, because of the side-looking nature of the SAR. Since the length of the layover on a ground-range SAR image is proportional to the building height, it can be used to estimate this height. We shift the building footprint obtained from 2D GIS data toward the sensor direction. The proposed method was applied to a TSX image of Lima, Peru in the HighSpot mode with a resolution of about 1 m. The results were compared with field survey photos and an optical satellite image, and a reasonable level of accuracy was achieved.
The seismic vulnerability of buildings located in Pisco, Peru, was studied using damage survey data and seismic ground motion simulation. Inventory and damage information for more than 10,000 buildings was registered in survey data compiled by CISMID at Peru’s National University of Engineering. The soil classes in the Pisco district were classified into three zones based on the predominant periods of microtremors at 85 sites, and damage ratios were calculated for each zone. Surface ground motions in each zone were estimated on the basis of base-rock motion simulation and shallow soil-column response analysis. Finally, fragility curves for adobe and brick masonry buildings were derived in terms of PGA and PGV. The results were compared with fragility functions developed in other studies.
Pisco was the area most damaged by the 2007 Peru earthquake. The purpose of this research is to develop possibilities of using satellite imagery to monitor post-disaster urban recovery processes, focusing on the urban change in Pisco between 2007 and 2011. To this end, the authors carried out field surveys in the city in 2012 and 2013 and also examined previous surveys to determine that building reconstruction peaked between 2008 and 2009. After analyzing the five-year recovery process, the authors compared its reconstruction conditions by visual interpretation with those by image analysis using satellite image. An accuracy of 71.2% was achieved for the visual interpretation results in congested urban areas, and that for developed districts was about 60%. The result shows that satellite imagery can be a useful tool for monitoring and understanding post-disaster urban recovery processes in the areas in which conducting long-term field survey is difficult.
Looking ahead ten or twenty years, the urban population will inevitably increase in the Lima Metropolitan Area (LMA) of Peru. Various urban development projects will naturally be implemented in order to accommodate the additional population, and this could increase vulnerability to disasters from earthquakes if no corrective actions are taken. A computer simulation model termed LIMA-UVEQ was developed so that we could forecast the region’s vulnerability to earthquake disasters over the next twenty years. Two cases were evaluated: one where some earthquake damage mitigation measures are incorporated with urban development projects and another where no such measures are implemented. With the modeling results, we then try to propose an appropriate policy mix that can be implemented in line with urban growth.
After the 2011 Great East Japan (Tohoku) earthquake and tsunami disaster, reduction and avoidance of potential losses from disasters have received much attention. We focused on disaster education which is defined simply as disaster risk reduction education. We developed new educational tool for disaster education. We called the new game-book the “disaster simulation game-book.” This study was designed to investigate the beneficial effects of experimental learning using the disaster simulation game-book on disaster education for children. Thirty four junior high school students participated in the study. They were randomly assigned into learning with the game book or learning with the cartoon film groups. They answered some questions before and after learning disaster. The results clearly demonstrated the beneficial effects of game-book learning on attitudes of disasters measured for question (If a large earthquake occurred, could you overcome difficulty from the earthquake on your own?) and question (If a large earthquake occurred, do you think that you could safely get clear away?). We discussed beneficial effects of the game-book on disaster education.
The Yura River in northern Kyoto Prefecture has long caused flood problems in its drainage basin. Specifically, areas downstream from Ayabe, where the river comes down from mountainous regions to a basin, frequently suffered from inundations, e.g., the Disaster Relief Law was applied eight times in the 60 years from 1953 to 2013. Against those background, river development projects, including levee construction and channel dredging, have been well underway since the late 1950s. The Ohno dam upstream on the main river was completed in 1961. However, the degree of flood safety remained low at that time. In 2004, the heaviest flood in the 50 years since 1953 occurred, followed in 2013 by a massive flood recording the highest water level since observations began at Fukuchiyama. The 2013 flood occurred in the midst of urgent levee construction and land raising based on a river infrastructure development project begun in response to a 2004 flood. This paper outlines damage from floods in 2004 and 2013 and shows the effects of these floods on the inundation depth of levees under development and the effects of the difference in rainfall characteristics in 2004 and 2013 on flood and fine sediment runoff. The effectiveness of the Ohno dam and misunderstandings by residents of the dam are also described. Important points in promoting river development from hard and soft measure are presented for making use of experiences the two disaster in the future.