An earthquake of preliminary magnitude 6.4 struck early today off the north coast of Puerto Rico, according to the U.S. Geological Survey (USGS).

The temblor's epicenter was 35 miles (57 km) north of Hatillo, Puerto Rico, and 61 miles (98 km) northwest of San Juan. It originated 17.4 miles (28 km) deep and struck at 12:04 a.m. local time (4:04 UTC), the USGS reports.

Moderate to light shaking was felt throughout the island. Some residents experienced minor damage, like falling objects in their homes, but there were no reports of major damage, according to the Associated Press

Earthquakes of the size of the one that struck today can cause significant damage, especially with poorly built structures. But the damage caused by any single event depends on the quake's depth, proximity to populated areas, building standards in the region, as well as the type of earthquake. The USGS frequently updates the magnitude of an event after more data is analyzed.

An earthquake's magnitude is a measure of the energy released at the source. It is just one predictor of the shaking that may ensue, which is affected by local and regional geology. Scientists know in a general sense what causes Earthquakes but are unable to predict specific quakes.

This article will be updated if significant additional information becomes available. Find more earthquake news here.