Recent performance improvements and enhanced capabilities of the OpenQuake-engine now make it possible to run highly complex hazard and risk analysis. We are pleased to showcase a few key findings from GEM’s state-of-the-art risk assessment for California using the OpenQuake-engine. Several risk metrics were calculated considering the full logic-tree of the UCERF3 model, and then a simple procedure is described to trim the logic tree.
Physical phenomena such as earthquakes have caused extensive human and economic losses in the past. In the last century, more than 80 destructive earthquakes have occurred, causing approximately 21,000 fatalities, almost a 1,000,000 homeless and economic losses exceeding 12 billion USD. To improve the understanding ofearthquake risk in the region, the Global Earthquake Model (GEM), in collaboration with the United States Agency for International Development (USAID), has led an initiative (Sub-Saharan Africa Hazard and Risk Assessment – SSAHARA) to create an open earthquake model for East Sub-Saharan Africa.
On April 16, 2016, a magnitude 7.8 (Mw) earthquake struck the northern coast of Ecuador, causing heavy damage and casualties in a widespread area. At the time of writing of this post, hundreds of buildings have been reported collapsed and more than 3,000 people have been affected. With such a striking impact, it is fundamental to respond efficiently and prepare for the recovery phase. This post aims at sharing some of these outcomes with the scientific and disaster risk reduction communities, hoping that they might prove useful in the identification of the regions where a higher level of damage is expected, as well as in the strategic planning of the recovery process.
As in many Latin American countries, the building stock, infrastructure and population in Colombia are mainly concentrated in a few regions. Antioquia’s Department, with a medium to high seismic hazard, is the second most populated department of the country with 6,534,746 inhabitants (14% of the country’s population). This study indicates that an event with a moderate magnitude is capable of causing extensive damage or collapse in more than 5 thousand unreinforced masonry residential buildings (click on the title to read more).
Costa Rica has experienced a considerable amount of violent earthquakes during the last four decades. The 1991 Limón earthquake, the greatest recorded event in the country of Mw 7.6, left a death toll of 48 and economic losses reaching $100 million USD. More recently, the Mw 6.1 Cinchona earthquake caused 40 fatalities and more than $500 million USD in damage. This study indicates that Costa Rica has an annual average economic loss of 105 million USD (click on the title to read more).
Risk from earthquakes (and natural hazards in general) is defined in a multitude of ways, yet earthquake risk is primarily the product of interactions between seismic hazard, the constructed environment, and the degree of vulnerability of people and property exposed to the threat. A number of approaches for understanding earthquake risk exist, but it is the interrelationships between these concepts that are becoming the focal point for politicians, stakeholders, and the general public (click on the title to read more).