December 2025 Seismic Activity Report: 67 Earthquakes (Max M3.6)
Complete analysis of Bay Area earthquake activity in December 2025. 67 total earthquakes recorded, 3 felt events. Trends, regional breakdown, and safety reminders.
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December 2025 Overview
The San Francisco Bay Area recorded 67 earthquakes in December 2025, with magnitudes ranging from M0.5 to M3.6.
Monthly Statistics
| Metric | Value |
|---|---|
| Total Earthquakes | 67 |
| Largest Earthquake | M3.6 |
| Average Magnitude | M1.88 |
| Felt Earthquakes (M3+) | 3 |
| Earthquake Swarms | 2 |
Magnitude Distribution
| Range | Count | Percentage |
|---|---|---|
| M0-2 (Micro) | 40 | 60% |
| M2-3 (Minor) | 24 | 36% |
| M3-4 (Light) | 3 | 4% |
| M4+ (Moderate+) | 0 | 0% |
Regional Breakdown
| Region | Earthquakes | Share |
|---|---|---|
| San Ramon | 36 | 54% |
| Sonoma | 8 | 12% |
| Gilroy | 7 | 10% |
| Santa Clara | 7 | 10% |
| Berkeley | 5 | 7% |
Weekly Trend
- Week of Dec 1: 28 earthquakes
- Week of Dec 8: 36 earthquakes
- Week of Dec 15: 0 earthquakes
- Week of Dec 22: 0 earthquakes
- Week of Dec 29: 0 earthquakes
Felt Earthquakes
These earthquakes were large enough to potentially be felt by residents:
M3.6 - 4 km SE of San Ramon, CA
- Date: Monday, December 8, 2025
- Time: 5:07 PM UTC
- Depth: 9.6 km
- View Details →
M3.3 - 6 km WSW of Kenwood, CA
- Date: Monday, December 1, 2025
- Time: 6:56 AM UTC
- Depth: 4.8 km
- View Details →
M3.1 - 6 km WSW of Kenwood, CA
- Date: Monday, December 1, 2025
- Time: 8:06 AM UTC
- Depth: 4.9 km
- View Details →
Swarm Activity
2 earthquake swarms were detected in December 2025:
- San Ramon Swarm
- Duration: Dec 8, 2025 - Dec 8, 2025
- Total earthquakes: 35
- Peak magnitude: M3.6
- Sonoma Swarm
- Duration: Dec 1, 2025 - Dec 3, 2025
- Total earthquakes: 7
- Peak magnitude: M3.3
Looking Ahead
The Bay Area sits atop several major fault systems including the San Andreas, Hayward, and Calaveras faults. Scientists estimate a 72% probability of a magnitude 6.7 or greater earthquake in the region within the next 30 years.
Stay Prepared
1. Before: Create an earthquake kit and family communication plan
2. During: Drop, Cover, and Hold On
3. After: Check for injuries, assess damage, and be prepared for aftershocks
Report felt earthquakesTopics covered
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