Lying on the Ring of Fire, the Guatemalan highlands and the Valle de la Ermita are frequently shaken by large earthquakes. The last large tremor to hit the Guatemala City region occurred in the 1976, on the Motagua Fault, a left-lateral strike-slip fault that forms the boundary between the Caribbean Plate and the North American Plate. The 1976 event registered 7.5 on the moment magnitude scale. Smaller, less severe tremors are frequently felt in Guatemala City and environs.