Seismic activity in the United States: The tremors recorded during the last period

In the United States, seismic activity of varying intensity is constantly occurring, affecting multiple regions across the country from Alaska to Puerto Rico. According to the latest data from the United States Geological Survey (USGS), the agency responsible for monitoring these phenomena, a significant series of tremors has been documented over the past few hours. Below is a detailed analysis of the most relevant seismic events captured by the U.S. monitoring network.

Overview of Recorded Seismic Activity

In the last 24 hours, USGS identified a total of 27 earthquakes in North America and the Caribbean with magnitudes greater than 2.5 on the Richter scale. Of these, nine occurred within U.S. territory or its associated jurisdictions. The strongest quake reached a magnitude of 4.2 and was located eight kilometers from Black Eagle, Montana, marking a significant event in the Rocky Mountains region.

This concentration of tremors reflects the ongoing tectonic activity characteristic of North America, where multiple fault systems generate periodic movements. Data provided by USGS allows scientists and authorities to maintain an accurate real-time record of geological activity.

Earthquakes in Alaska: Region of Highest Seismic Activity

Alaska, as the most geologically active region in the country, recorded most of the documented tremors. Notable events include:

• A magnitude 3.7 quake located 74 kilometers north of Yakutat, occurred on January 29 at 22:59 UTC
• A magnitude 3.5 event recorded 61 kilometers east of Sand Point, at 21:01 UTC on January 29
• A magnitude 3.1 earthquake 194 kilometers southeast of Akutan, on January 30 at 02:02 UTC
• A 2.8 magnitude tremor located 23 kilometers west of Akhiok, recorded at 11:52 UTC on January 30

The clustering of these seismic movements in Alaska is due to its position in the Bering Plate subduction zone, a high-energy tectonic convergence region that explains the frequency and magnitude of earthquakes in this area.

Seismic Activity in Continental Territories and Other Jurisdictions

Beyond Alaska, other U.S. territories also experienced significant seismic activity:

Rocky Mountains Region: The most notable event outside Alaska was a magnitude 4.2 tremor near Black Eagle, Montana, located 8 kilometers northeast, recorded on January 29 at 19:41 UTC. This was the strongest quake in the analyzed period. Additionally, a magnitude 2.7 earthquake was documented 5 kilometers northwest of Malmstrom Air Force Base, also in Montana.

Colorado: The region experienced two tremors on January 30. The first, of magnitude 2.8, was located 29 kilometers south of Weston, and the second, of 2.5, occurred 32 kilometers southwest of Segundo.

Texas: Two events were recorded: a magnitude 2.7 quake 12 kilometers west of Stanton (January 30, 07:25 UTC), and another of 2.5 degrees 35 kilometers northwest of Toyah (January 29, 18:32 UTC).

New Mexico: A magnitude 3.9 tremor was documented 32 kilometers north of Cimarron on January 30 at 07:20 UTC.

Puerto Rico: This jurisdiction experienced seismic activity with a magnitude 3.1 quake located 5 kilometers east-southeast of Maricao (January 30, 07:53 UTC), and another of 3.3 degrees 133 kilometers northeast of Vieques (January 29, 16:41 UTC).

Oregon: A magnitude 3.5 earthquake was detected 259 kilometers southwest of Pistol River on January 30 at 05:30 UTC.

California Geology and the San Andreas Fault: Context of Seismic Risk

The San Andreas Fault is one of the most studied geological structures in North America, extending approximately 1,300 kilometers across California. This geological fault marks the boundary contact between the Pacific Plate and the North American Plate, creating a zone of continuous friction that produces ongoing seismic activity.

Scientists and geologists warn of the possibility that a major earthquake could occur in this region in the future, popularly known as the “Big One.” An event of this magnitude, 8.0 or higher, could cause widespread devastation, particularly affecting densely populated urban centers like Los Angeles and San Francisco, where millions of people would be at risk.

Although decades have passed since the last major earthquakes in California, historical data documented by USGS helps understand the potential scale of such events. The 1906 San Francisco earthquake reached a magnitude of 7.8, and the 1857 Fort Tejon earthquake had a magnitude of 7.9. These events serve as references for estimating the destructive potential of the next large quake in California.

In response, local and federal authorities regularly conduct emergency drills, update structural safety protocols, and develop public awareness campaigns aimed at preparing populations for protective measures before, during, and after a major seismic event.