n unusual cluster of moderate earthquakes took place over two days west of the Volcán Irazú, according to the Red Sismológica Nacional.
A report listed 24 quakes between 4.8 and 2.3 magnitude from 8:19 p.m. Monday and 7:09 a.m. Tuesday.
The earthquake agency attributed the quakes to a local fault. The 10-kilometer fault is well known and even has a name, Lara. The location is north of the central canton of Cartago.
The flurry would be of mostly academic interest if the locations were not so close to the twin volcanos. Turrialba has been erupting periodically, and Irazú had a run of eruptions and emission of gas two years ago.