Already bracing for tropical depression, Puerto Rico rocked by 6.0 earthquake The island is preparing for a tropical depression.

Already bracing for a tropical system in the next 24 hours, Puerto Rico was hit by an earthquake late Monday.

The earthquake measured a magnitude of 6.0, according to the U.S. Geological Survey, and was located about 46 miles northwest of the island. There is no tsunami threat for the island, or the neighboring U.S. Virgin Islands.

There were at least seven aftershocks over 4.0 magnitude in the hour following the initial quake, which struck at 11:24 p.m. An aftershock of 5.1 was measured just nine minutes after the initial quake, according to the National Weather Service.

An official for the island’s Office of Emergency Management told ABC News that the agency’s regional offices are in contact with municipalities to get an early report on any damage. At the moment, there are no reports of damage or injuries.

The Office of Emergency Management’s offices were already open around the clock ahead of Tropical Depression Karen.

The official said the quake and aftershocks will not impact the agency ahead of Karen.

Puerto Rico Gov. Wanda Vazquez tweeted late Monday, "We hope everyone is well. ... It is important to remain calm during these natural events to guarantee security."

The preliminary magnitude for the quake was measured at 6.3 magnitude, according to the NWS.

The island already closed schools on Tuesday in preparation for Karen, which is expected to lash Puerto Rico with gusty winds and rain of as much as 4 to 8 inches. The island was spared just last week by Hurricane Humberto as it skirted north of the island.