Earthquake Scenarios for Risk Management: A Case Study of Three Cities in Latin America

Seismic scenarios support the creation of a common understanding of the consequences of earthquakes in a region and help evaluate the resources that may be needed to mitigate its effects or to cope with the emergency that it can trigger. Stakeholders can visualize the most affected areas within the region of influence, the number and spatial distribution of casualties, economic losses, and damaged and collapsed buildings. Thus, earthquake scenarios allow for identification of weaknesses and strengths in the emergency management system, evaluation of the required measures for reducing the risk, and improving preparedness and recovery in future events.

Partnering with the risk management offices of Quito, Ecuador; Cali, Colombia; and Santiago de los Caballeros, Dominican Republic, the Global Earthquake Model (GEM) Foundation and the United States Geological Survey (USGS) teams conducted a multi-year research effort to co-develop a set of earthquake scenarios and generate a series of impact products under the auspices of the TREQ project (Training and Communication for Earthquake Risk Assessment, www.globalquakemodel.org/proj/treq). Given that the consequences of a specific seismic event can change significantly depending on the earthquake rupture characteristics, such as magnitude, hypocentral depth, and distance to the exposed assets, several relevant earthquake scenarios were developed for each city. The earthquake ruptures were selected considering two approaches: i) identification of relevant historical events whose magnitude, faulting style and rupture geometry are well-known; and ii) using a hazard-based approach that considers the hazard disaggregation results from the probabilistic seismic hazard analysis (i.e., identification of the combination of distances from and magnitudes of seismogenic sources that contribute the most to the seismic hazard at each urban center).

We discuss the process of scenario development and the key results associated with each city. Results are summarized through one-page profiles that provide a baseline of the potential impacts to stimulate further actions. The input models and results are openly available in the repository https://github.com/gem/treq-riesgo-urbano.