QCOSTARICA – A 5.7 magnitude earthquake, with its epicenter in San Jose, it at 11:01 pm Saturday, October 31, and was strongly perceived in different parts of the Central Valley.
The Red Sismológica Nacional (RSN) – National Seismological Network – reported that the earthquake occurred 1 km north of San Juan de Tibas, San José, at a depth of 77 kilometers.
For its part, the Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori) – Volcanological and Seismological Observatory of Costa Rica – located the epicenter in the Luján neighborhood, in San José, at a depth of 77 kilometers and a magnitude of 5.4 degrees and was due to the subduction of the Coco plate (deformation of the plate at intermediate depth).
According to Ovsicori, the origin of the quake was due to internal deformation of the Coco plate and felt in the Central Valley, Turrialba, Sarapiquí, Miramar de Puntarenas, San Vito de Coto Brus, Cañas Guanacaste
The The United States Geological Survey (USGS) reported the quake a 5.2 magnitude.
On social networks, reports indicated that the earthquake felt strong in different parts of San José, Heredia, Cartago and Alajuela.
For its part, the Cruz Roja (Red Cross) said it had no reports of damage or of people affected by the earthquake.
“They say that it felt very strong throughout the Greater Metropolitan Area (GAM), but there are no people injured or damaged,” the Red Cross said.
The Laboratorio de Ingeniería Sísmica de la Universidad de Costa Rica (UCR) – Seismic Engineering Laboratory of the University of Costa Rica – reported that the maximum values of the tremor were registered in the cantons of Puriscal, Acosta and Turrubares.
“The depth of this event had seismic waves reach distant places such as Quepos, Parrita and Jacó where intensities JMA = 3 are registered, although their epicenter is located in the Central Valley and its magnitude is moderate,” it explained.
Así se distribuyen los valores máximos de aceleración (que correlacionan con la intensidad): Puriscal, Acosta, Turrubares, Grecia y Ochomogo. En este caso de sismo profundo, sitios altos en las zonas montañosas y de suelos blandos (Grecia) amplifican la señal. pic.twitter.com/5RTDExks0r
— LISUCR (@LISUCR) November 1, 2020
According to the UCR laboratory, the Japan Meteorological Agency (JMA) seismic intensity scale quantifies how much ground-surface shaking takes place at measurement sites distributed throughout an affected area. The JMA scale is expressed in levels of seismic intensity from 0 (weakest) to 7 (strongest).