Earthquakes recorded in California and across the United States: magnitudes and precise locations as of January 30

In the 24 hours prior to January 30, the United States experienced intense seismic activity distributed across multiple regions. The most significant tremors were concentrated in Alaska, followed by notable activity in Texas, Colorado, Montana, and New Mexico. According to official data from the United States Geological Survey (USGS), dozens of earthquakes were detected throughout North America and the Caribbean, with more than half located within U.S. territory or its territorial jurisdictions.

Documented seismic activity: geographic distribution patterns

Analysis of the seismic events revealed a notable concentration in Alaska, where tremors of varying magnitudes were recorded. The California area and its surroundings also showed activity, though with less intensity compared to other regions of the country. In total, within the United States and its territories, nine events with a magnitude greater than 2.5 on the Richter scale were identified, establishing this period as a time of high tectonic activity.

The most powerful documented event was a magnitude 4.2 quake located eight kilometers from Black Eagle, Montana, which occurred on January 29 at 19:41 UTC (12:41 local time in Helena). This quake was followed by others of lesser intensity but equally relevant for ongoing monitoring of seismically active zones.

Complete record of tremors: epicenters, times, and precise magnitudes

Data compiled by the USGS include the following detailed information for each recorded seismic event:

Alaska Region:

• 23 km west of Akhiok: magnitude 2.8 (January 30, 11:52 UTC / 02:52 Anchorage)
• 28 km northwest of Happy Valley: magnitude 2.6 (January 30, 11:44 UTC / 02:44 Anchorage)
• 40 km east of Pedro Bay: magnitude 3.0 (January 30, 02:07 UTC / 17:07 January 29 in Anchorage)
• 194 km southeast of Akutan: magnitude 3.1 (January 30, 02:02 UTC / 17:02 January 29 in Anchorage)
• 74 km north of Yakutat: magnitude 3.7 (January 29, 22:59 UTC / 13:59 Anchorage)
• 61 km east of Sand Point: magnitude 3.5 (January 29, 21:01 UTC / 12:01 Anchorage)
• 59 km southeast of Sand Point: magnitude 3.3 (January 29, 20:25 UTC / 11:25 Anchorage)
• 94 km north of Yakutat: magnitude 3.5 (January 29, 18:37 UTC / 09:37 Anchorage)
• 104 km southeast of McCarthy: magnitude 3.1 (January 29, 18:36 UTC / 09:36 Anchorage)
• 47 km northwest of Valdez: magnitude 2.6 (January 29, 15:16 UTC / 06:16 Anchorage)
• 64 km southeast of Adak: magnitude 2.6 (January 29, 13:21 UTC / 04:21 Anchorage)
• 288 km southwest of Adak: magnitude 3.8 (January 29, 12:57 UTC / 03:57 Anchorage)

Rocky Mountains and Texas Region:

• 29 km south of Weston, Colorado: magnitude 2.8 (January 30, 11:06 UTC / 04:06 Denver)
• 32 km southwest of Segundo, Colorado: magnitude 2.5 (January 30, 11:06 UTC / 04:06 Denver)
• 12 km west of Stanton, Texas: magnitude 2.7 (January 30, 07:25 UTC / 01:25 Austin)
• 35 km northwest of Toyah, Texas: magnitude 2.5 (January 29, 18:32 UTC / 12:32 Austin)
• 10 km southeast of Pearsall, Texas: magnitude 2.6 (January 29, 17:02 UTC / 11:02 Austin)

New Mexico and Montana Region:

• 32 km north of Cimarron, New Mexico: magnitude 3.9 (January 30, 07:20 UTC / 00:20 Santa Fe)
• 5 km northwest of Malmstrom Air Force Base, Montana: magnitude 2.7 (January 30, 00:46 UTC / 17:46 January 29 in Helena)
• 8 km northeast of Black Eagle, Montana: magnitude 4.2 (January 29, 19:41 UTC / 12:41 Helena)

Overseas Territories:

• 5 km east-southeast of Maricao, Puerto Rico: magnitude 3.1 (January 30, 07:53 UTC / 03:53 San Juan)
• 133 km northeast of Vieques, Puerto Rico: magnitude 3.3 (January 29, 16:41 UTC / 12:41 San Juan)
• 259 km southwest of Pistol River, Oregon: magnitude 3.5 (January 30, 05:30 UTC / 21:30 January 29 in Salem)

The San Andreas Fault: a permanent geological laboratory

The San Andreas Fault represents one of the most studied and monitored geological systems on the planet. This structure extends approximately 1,300 kilometers across California, marking the boundary between the Pacific Plate and the North American Plate. Its importance lies in its near-constant seismic activity, generating thousands of small tremors annually that, while imperceptible to most people, provide valuable data to scientists.

Seismological communities pay particular attention to this region due to the latent risk of a catastrophic event known as the “Big One.” This would be a magnitude 8 or higher quake, whose occurrence is considered inevitable based on geological records, though its exact timing remains unpredictable. Such an earthquake could cause widespread devastation in densely populated areas like Los Angeles, San Francisco, and surrounding regions.

Historical context: major earthquakes that shook the region

USGS records document two of the most significant seismic events in recent California history. The first was the 1906 San Francisco earthquake, which reached a magnitude of 7.8 and caused massive destruction in the city and surrounding areas. Decades earlier, the 1857 Fort Tejon earthquake registered a magnitude of 7.9, leaving an indelible mark in the region’s seismic archives. These historical precedents underscore the importance of continuous monitoring and preparedness for future large-magnitude events.

Preparedness measures and public awareness

Given the certainty that larger earthquakes will occur in the future, U.S. authorities constantly conduct emergency drills, thoroughly review safety protocols for critical infrastructure, and run educational campaigns aimed at the public. These initiatives seek to ensure that every citizen understands what actions to take before, during, and after a quake, thereby minimizing human and material losses. Seismic education has become an essential component of urban planning in regions prone to such natural phenomena.