Benefits of global earth observation missions for disaggregation of exposure data and earthquake loss modeling: evidence from Santiago de Chile

Exposure is an essential component of risk models and describes elements that are endangered by a hazard and susceptible to damage. The associated vulnerability characterizes the likelihood of experiencing damage (which can translate into losses) at a certain level of hazard intensity. Frequently, the compilation of exposure information is the costliest component (in terms of time and labor) of risk assessment procedures. Existing models often describe exposure in an aggregated manner, e.g., by relying on statistical/census data for given administrative entities. Nowadays, earth observation techniques allow the collection of spatially continuous information for large geographic areas while enabling a high geometric and temporal resolution. Consequently, we exploit measurements from the earth observation missions TanDEM-X and Sentinel-2, which collect data on a global scale, to characterize the built environment in terms of constituting morphologic properties, namely built-up density and height. Subsequently, we use this information to constrain existing exposure data in a spatial disaggregation approach. Thereby, we establish dasymetric methods for disaggregation. The results are presented for the city of Santiago de Chile, which is prone to natural hazards such as earthquakes. We present loss estimations due to seismic ground shaking and corresponding sensitivity as a function of the resolution properties of the exposure data used in the model. The experimental results underline the benefits of deploying modern earth observation technologies for refined exposure mapping and related earthquake loss estimation with enhanced accuracy properties

Reporte del Taller para la Evaluación Participativa del Riesgo Sísmico y la Resiliencia en San José, Costa Rica (Translated title: Participatory assessment of seismic risk and resilience in Costa Rica)

Costa Rica is located along the Pacific Ring of Fire. The country is divided into seven provinces: San José, Alajuela, Cartago, Heredia, Guanacaste, Puntarenas y Limón. In the framework of the Assessing and Mitigating Earthquake Risk in the Caribbean and Central America (CCARA) project, and jointly with the municipality of San Jose and the National Commission of Emergencies (CNE) of Costa Rica, we undertook a participatory assessment of seismic risk and resilience-based using the Resilience Performance Scorecard (RPS) methodology with representatives of the Provinces of San Jose and Guanacaste. The RPS is a self-evaluation methodology to empower the community to assess resilience parameters based on primary source information. This methodology consisted on 39 questions distributed in six dimensions: Legal and Institutional Arrangements; Social Capacity; Critical Services and Public Infrastructure Resilience; Emergency Preparedness, Response and Recovery; Planning, Regulation and Mainstreaming Risk Mitigation and Awareness and Advocacy. The participants have divided two groups: officials from the government institutions of San Jose and representatives of NGOs’ present in Costa Rica and community leaders from the cantons of San José, Escazú, Desamparados, Aserrí, Alajuelita and Vásquez de Coronado from the province of San Jose and Cañas en Guanacaste. The community leaders selected by the CNE already belonged to a group of people who participate in activities of capacity building in disaster prevention and emergency attention. The attendance numbers show a high representation of women, which was one of the objectives of the RPS in San Jose. Both exercises were undertaken in the local language: Spanish. Regarding the dimension of Legal and Institutional Arrangements, it was clear that the community leaders were aware of the existence of a land use plan, but the application is not visible for them. The government officials know very well the National Law of Emergency and Risk Prevention (Legislative Decree N.º 8488 - Record N.º 14.452), thus it is clear for them who are the responsibility of the Disaster Risk Reduction (DRR) activities, but not for the citizen. There are big differences between officials and the community leaders in the perception of topics related to Social Capacities such as decision making, cultural heritage, availability of social programs, accessibility and evacuation routes, coverage of health services for vulnerable population and the immigration. In regards to critical services and public infrastructure resilience, it was concluded from the discussion that it is a necessary renewal of lifelines with the participation of the institutions in charge of the DRR and community leaders. With respect to Emergency Preparedness, Response and Recovery, it was found that very few participants keep some kind of available provisions in case of an earthquake and that the municipality does not have a local center for the implementation and coordination of emergency response. Officials and community leaders agree that the level of awareness of population regarding the impact of an earthquake on their impact and their life is almost none, then it is necessary to promote the insurance among the population. The officials and community leaders have a similar opinion related to the activities involved in the planning, regulation and mainstreaming of risk mitigation. In conclusion, the result of the application of this methodology reports medium to high levels of seismic risk and resilience perceived among the sampling population in the six dimensions that the methodology was tested. The main recommendation is to increase the participation of the community in the actions oriented to enhance resilience in Costa Rica

Benefits of global earth observation missions for disaggregation of exposure data and earthquake loss modeling: evidence from Santiago de Chile

Funder: Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (4202)AbstractExposure is an essential component of risk models and describes elements that are endangered by a hazard and susceptible to damage. The associated vulnerability characterizes the likelihood of experiencing damage (which can translate into losses) at a certain level of hazard intensity. Frequently, the compilation of exposure information is the costliest component (in terms of time and labor) of risk assessment procedures. Existing models often describe exposure in an aggregated manner, e.g., by relying on statistical/census data for given administrative entities. Nowadays, earth observation techniques allow the collection of spatially continuous information for large geographic areas while enabling a high geometric and temporal resolution. Consequently, we exploit measurements from the earth observation missions TanDEM-X and Sentinel-2, which collect data on a global scale, to characterize the built environment in terms of constituting morphologic properties, namely built-up density and height. Subsequently, we use this information to constrain existing exposure data in a spatial disaggregation approach. Thereby, we establish dasymetric methods for disaggregation. The results are presented for the city of Santiago de Chile, which is prone to natural hazards such as earthquakes. We present loss estimations due to seismic ground shaking and corresponding sensitivity as a function of the resolution properties of the exposure data used in the model. The experimental results underline the benefits of deploying modern earth observation technologies for refined exposure mapping and related earthquake loss estimation with enhanced accuracy properties.</jats:p