The Ground Beneath Our Feet: South Bay Shakes

Residents across Los Angeles’ coastal communities jolted awake to an unnerving reality yesterday when a magnitude 3.4 earthquake struck near Manhattan Beach at 12:15 PM PDT. Centered just 14 km offshore near the Palos Verdes Peninsula at a depth of 11.3 km, the tremor rippled through Santa Monica, Los Angeles, and beyond—a visceral reminder of California’s volatile geology 2.

This event punctuated a week of heightened seismic activity, with over 25 minor quakes (magnitudes 0.5–2.5) rattling the LA Basin since June 3. Most notably, a magnitude 2.5 quake shook Walnut Park on June 9—the strongest inland event—followed by clusters near Fontana, Loma Linda, and a series of probable quarry explosions near Corona 1.

Real-Time Quake Map: Where the Earth Moved

Recent significant tremors (June 5–10, 2025):

Source: Caltech/USGS Advanced National Seismic System 1

The Hidden Tsunami Threat: Waves Within 10 Minutes

While yesterday’s quake caused no damage, experts warn Angelenos to confront a far deadlier scenario: near-shore tsunamis. According to new hazard maps published by the California Geological Survey, an earthquake just off LA’s coast could send life-threatening waves ashore in as little as 10 minutes—too fast for official alerts to reach most residents 3.

Projected tsunami heights reveal startling risks:

• Santa Monica Pier: 8-foot waves
• Long Beach: 8-foot inundation
• Manhattan Beach: 7-foot surge
• Malibu: 9-foot walls of water
• Catalina Island: *30-foot devastation*

Reginald Harrison, Long Beach’s disaster preparedness director, stresses: “Tsunamis are a rare but real threat. If you’re near the beach during strong shaking, move to higher ground immediately”.

Evacuation Chaos: Why “Driving Out” Could Be Deadly

Emergency planners face a nightmare scenario in densely packed coastal zones like Balboa Island, Naples Island (Long Beach), and Mission Beach (San Diego). Newport Beach estimates 45,000 residents live in tsunami flood zones—yet a full evacuation could take 5 hours, far longer than the 10–20 minute wave arrival time 3.

During December 2024’s Humboldt County tsunami scare, chaos erupted:

• Highway 1 jammed with cars fleeing Pacifica

• Berkeley residents drove into low-lying areas

• Confusion over evacuation zones paralyzed responses

“Avoid low-lying areas—don’t just jump in your car,” urges San Mateo County’s Shruti Dhapodkar. *“In Santa Monica, walking up to the 100-foot bluffs saves lives faster than driving inland”* 3.

 Survival Strategies: From “Drop, Cover” to Vertical Refuge

With near-shore tsunamis allowing minimal escape time, officials emphasize targeted preparedness:

• Know Your Zone: Check CGS Tsunami Hazard Maps (updated 2025)
• Walk, Don’t Drive: Reach high ground (>100 ft) within 15 minutes on foot
• Vertical Evacuation: In flat zones like Marina del Rey, head to upper floors of steel-reinforced buildings
• Disability Plans: San Francisco implementing accessibility protocols by 2027

Jennifer Lazo of LA Emergency Management clarifies: “For most of LA, evacuating just a few blocks inland suffices. Save long-distance driving for distant-source tsunamis” 3.

FAQ: Your Earthquake and Tsunami Questions Answered

1. Was this 3.4 quake “the Big One”?
No. Scientists consider magnitudes >7.0 likely to cause major damage. This was a minor tectonic release—common along LA’s fault network 12.

2. Do all undersea earthquakes cause tsunamis?
Only those that vertically displace seafloor rock. Strike-slip faults (like San Andreas) rarely trigger tsunamis, but thrust faults near the coast pose high risk 3.

3. Why were explosions listed in quake data?
Caltech’s system flags seismic events from quarry blasts (e.g., Corona on June 6). These aren’t tectonic but appear in feeds 1.

4. How can I report feeling a quake?
Use the USGS “Did You Feel It?” tool to share experiences and build public shake maps 10.

The Bottom Line: Vigilance Without Alarm

As the June Gloom lifts, Angelenos face a dual reality: the familiar nuisance of minor quakes and the existential—yet manageable—threat of tsunamis. While the 3.4 Manhattan Beach tremor rattled dishes, it also rattled complacency.

Katie Eing, Newport Beach emergency coordinator, frames our path forward:

“Know your zone, not your fear. Understand whether you walk, drive, or shelter upstairs. That knowledge turns panic into preparedness.”

For today, the seismic drums beat softly. But in earthquake country, readiness isn’t paranoia—it’s survival poetry written in fault lines and flood zones.