Very strong and shallow M6.4 earthquake hits San Juan, Argentina

A very strong earthquake registered by the USGS as M6.4 hit San Juan, Argentina at 02:46 UTC (23:46 LT) on January 19, 2021. The agency is reporting a depth of 20 km (12.4 miles). EMSC is reporting the same magnitude and depth.
The epicenter was located about 29 km (18 miles) WSW of Pocito (population 40 969), 43 km (27 miles) SW of San Juan (population 447 048), 45 km (28 miles) SW of Santa Lucia (population 43 565), and 46 km (29 miles) SW of Villa Paula de Sarmiento (population 19 092), Argentina.
There are about 750 000 people living within 100 km (62 miles).
1 000 people are estimated to have felt very strong shaking, 651 000 strong, 216 000 moderate, and 6 561 000 light.
Image credit: TW/SAM, Google
The USGS issued a yellow alert for shaking-related fatalities. Some casualties are possible and the impact should be relatively localized. Past events with this alert level have required a local or regional level response.
A green alert was issued for economic losses. There is a low likelihood of damage.
Overall, the population in this region resides in structures that are resistant to earthquake shaking, though vulnerable structures exist. The predominant vulnerable building types are adobe block and rubble/field stone masonry construction.
Recent earthquakes in this area have caused secondary hazards such as landslides and liquefaction that might have contributed to losses.
The quake was followed by a series of aftershocks, including M5.0 at 03:03 UTC, M4.9 at 03:08 UTC, M5.3 at 03:37 UTC, M4.9 at 03:51 UTC, and M4.8 at 04:01 UTC.
The governor of San Juan urged people to stay calm and 'put into practice all the measures that we have learned to prevent incidents.'
Initial reports mention houses damaged in the small town of Media Agua, damaged roads, power outages, and injuries.
There are currently no reports of casualties or serious damage.
Estimated population exposure to earthquake shaking
Selected cities exposed
Regional seismicity
Featured image credit: TW/SAM, Google
If you value what we do here, create your ad-free account and support our journalism.
Your support makes a difference
Dear valued reader,
We hope that our website has been a valuable resource for you.
The reality is that it takes a lot of time, effort, and resources to maintain and grow this website. We rely on the support of readers like you to keep providing high-quality content.
If you have found our website to be helpful, please consider making a contribution to help us continue to bring you the information you need. Your support means the world to us and helps us to keep doing what we love.
Support us by choosing your support level – Silver, Gold or Platinum. Other support options include Patreon pledges and sending us a one-off payment using PayPal.
Thank you for your consideration. Your support is greatly appreciated.
Sincerely,
Teo Blašković
Commenting rules and guidelines
We value the thoughts and opinions of our readers and welcome healthy discussions on our website. In order to maintain a respectful and positive community, we ask that all commenters follow these rules:
We reserve the right to remove any comments that violate these rules. By commenting on our website, you agree to abide by these guidelines. Thank you for helping to create a positive and welcoming environment for all.