Per U.S. Geological Survey stats cited by the Associated Press, the quake struck approximately 49 miles off the island’s northwest coast at a shallow depth of 6 miles and resulted in three aftershocks varying between 4.7 and 4.6 magnitudes within less than an hour.
"I rushed into my son's room," 46-year-old San Juan resident Yahaida Zabala said of waking up to the quake, which she said swayed her building around 11:23 p.m. "He was sitting like he was paralyzed."
The latest word from Emergency Management Agency officials at the time of this writing was that there were no "immediate reports" of damage, nor was there a risk of tsunami.
The quake is said to be the strongest to be felt on the island in several years, with a January 2014 6.4 tremor said to be the most recent comparable example. Meanwhile, the National Guard has been activated in the region for the impending arrival of Tropical Depression Karen. Tuesday is projected to bring possible heavy rains, not to mention warnings for possible landslides and flooding, with schools and government offices currently closed as a precaution.