Fault Lines Near Washington, D.C.: Not in the District
No major fault line runs through Washington, D.C. proper. The District sits on the Atlantic Coastal Plain—relatively stable, sedimentary geology.
Nearest Significant Fault Zones
| Feature | Distance | Characteristics |
|---|
| Eastern Mountain Front Thrust Fault | ~70 mi W (Shenandoah Valley) | Ancient (Paleozoic); low activity; Mmax ~5.5–6.0 |
| Central Virginia Seismic Zone | ~40 mi SW (Mineral, VA) | 2011 M5.8 quake epicenter; diffuse, not single fault |
| Stafford Fault System | ~35 mi S (Stafford, VA) | Mesozoic rift-related; minor historical seismicity |
| Brandywine Fault (MD) | ~25 mi SE | Minor; 1993 M3.4 event |
| Ramapo Fault (NY/NJ) | ~180 mi NE | Major NE structure; M5+ potential |
DC's Seismic Risk Profile
- PGA (Peak Ground Accel.): 2–4%g (2% in 50yr) — Low
- Notable felt quakes: 2011 Mineral, VA (M5.8) — cracked Washington Monument, National Cathedral; 1886 Charleston (M7.0) — felt strongly
- Building codes: IBC 2015+ with seismic provisions for new construction
- Critical infrastructure: Retrofit programs ongoing (Monument, Capitol, bridges)
Why It Matters
While not on a plate boundary, DC faces intraplate earthquake risk—rare but potentially damaging due to dense masonry stock, deep sediment amplification, and high-value infrastructure. The 2011 quake caused $200–300M damage regionally.
Bottom line: No fault in DC, but close enough to feel—and occasionally be damaged by—neighbors' earthquakes.
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