A minor earthquake with a magnitude of 2.1 struck near Alum Rock, California, early on November 20, 2023. The U.S. Geological Survey reported the quake occurred at 4:56 a.m., approximately four miles east of Alum Rock, at a shallow depth of just two miles.
Recent Seismic Activity in the Region
This latest tremor is part of a series of significant earthquakes recorded in the area within the past week. Three quakes registering magnitudes of 2.5 and above have been noted, including:
- 3.3 magnitude quake southeast of San Ramon on November 17
- 3.0 magnitude quake east of Seven Trees on November 18
- 2.6 magnitude quake southeast of San Ramon on November 18
Understanding Earthquake Magnitudes
The magnitude of an earthquake indicates the energy released during an event and has replaced the older Richter scale in scientific assessments. Generally, tremors between 2.5 and 5.4 can be felt, although they tend to cause minimal damage.
On a global scale, it’s estimated that around 500,000 earthquakes occur each year, with approximately 100,000 felt by people and about 100 causing damage.
What to Do During an Earthquake
Preparedness is vital during seismic events. Here are expert-recommended safety measures:
- If driving: Pull over to a safe spot and set your parking brake.
- If in bed: Turn face down and use a pillow to protect your head.
- If outdoors: Move away from buildings and avoid going indoors.
- If indoors: Stay put, avoiding doorways, and seek shelter under sturdy furniture.
Officials advise adopting the “Drop, Cover, and Hold On” technique. Drop to your hands and knees, cover your head and neck, and hold on to something stable until the tremors cease.
Post-earthquake, it’s important to remain vigilant for aftershocks, and to report any damage or hazardous conditions, such as leaking gas or downed power lines.
For those who felt the recent 2.1 magnitude quake near Alum Rock, the U.S. Geological Survey encourages reporting the experience through its official Felt Report form, aiding in the collection of seismic data.
