Peru is a highly seismic country: This is demonstrated by the nearly 200 low intensity earthquakes reported by the Geophysical Institute of Peru (IGP) year after year. In addition to this, scientific evidence indicates that, at any time, a earthquake of great magnitude it would occur on the central Peruvian coast, affecting millions of people.
It is in this area where the vast majority of these earthquakes have their origin, due to the friction produced by the Nazca and South American plates when they move over each other.
Along the history, the area that includes Lima and Callao is the one that has registered the largest number of earthquakes in the country -and tsunamis as a consequence-, the most destructive being those that took place in the years 1586, 1655, 1687 and 1746.
The silence of seismic coupling zones
From the historical and spatial record of the telluric movements, it is possible to identify “seismic coupling zones”. According to Hernando Tavera, president of the IGP, this concept refers to those sites “that in the past have experienced the occurrence of large earthquakes and that, to date, after several decades or centuries have elapsed, they still do not repeat themselves”.
“If the plates do not move, it is assumed that they are locked and, therefore, accumulating warp to be instantly released when it exceeds the endurance limit. By knowing where the plates are locked, it is possible to know where the problems will occur. upcoming earthquakes”, Tavera points out in relation to those earthquakes greater than 7 degrees on the moment magnitude scale.
Almost three centuries have passed since the last big earthquake that was lived in Lima and Callao. This scenario makes the authorities agree that a seismic movement of values similar to that of 1746 is expected, that is, of degree 9 on the MM scale (momentum magnitude).
The great earthquake that awaits us
The telluric movement that Lima and Callao would face would release a strong amount of energy. In the case of the soils of Metropolitan Lima, shaking levels of 500 cm/s would be reached 2, an oscillation close to that experienced 276 years ago. For Callao, it is estimated values up to 900 cm/s2 from Ventanilla to the port area.
To understand the violence of the movement that is anticipated, we can draw on close examples. The Pisco earthquake in 2007 demanded acceleration levels of 400 cm/s 2 in the city of Ica and 80 cm/s 2 in Lima, that is, between 6 and 11 times less of the telluric movement that would be triggered in the central Peruvian coast at any moment, according to Tavera.
On the other hand, during the 2010 earthquake in Santiago de Chilesoil shaking level of up to 900 cm/s were recorded 2, similar to what is expected to happen in Callao. In this stage, the IGP forecasts that 14 million people and up to 4 million homes throughout the country would be affected.
Although Tavera emphasizes that this calculation does not detail the type or severity of the damage, it is valid for deploying a series of actions at the institutional, community and family level. that guarantee the safety and well-being of all Peruvians before this possible earthquake.
Today, Monday, August 15, we commemorate the 15 years since the Pisco earthquake of a magnitude of 8.0 leaving almost 600 dead and more than 400 thousand people affected. As a commemoration of the victims of this disaster, the National Multihazard Drill at 3:00 pm, in which everyone should participate to identify safe areas, evacuation routes and a proper reaction that does not put us in danger.
RPP and Pacífico Seguros present the third stage of the Safe Community campaign, aimed at informing the public on how to prepare at the family and community level in the event of a major earthquake. Learn more by doing click here.