Earthquake risk monitoring for venues is the signal that most security ops managers ignore until they can't. The 2014 South Napa quake (M6.0) hit at 3:20 a.m., 12 hours before BottleRock's set times the same week — every venue within 50 miles of the epicenter spent the morning revalidating rigging, scaffolding, and the structural integrity of temporary infrastructure. SignalGuard surfaces live seismic activity at the venue continuously so the question "did you feel that?" gets answered with magnitude, depth, and distance in under 60 seconds.
What this signal monitors
The Earthquakes signal reports magnitude, distance from venue, depth, and timestamp for every USGS-detected seismic event in the past 7 days within a configurable radius (default 200 km). It catches both individual significant quakes and swarms — a cluster of small events that may not individually be threatening but collectively indicate fault stress.
Data sources
SignalGuard's usgsEarthquakeClient.js pulls the USGS Earthquake Hazards Program's all-week summary GeoJSON feed — free, no API key, updated every minute, global coverage. USGS is the authoritative seismic data source for North American events and aggregates international feeds (EMSC, JMA) for global coverage. The client filters the worldwide feed to events within the venue's radius using haversine distance and sorts by severity then magnitude then proximity.
How SignalGuard scores severity
Severity combines magnitude and distance: M6.0+ within 100 km is critical; M5.0+ within 100 km OR M4.0+ within 25 km is high; M4.0+ within 100 km OR M3.0+ within 25 km is medium. The overall level also bumps to medium when 8 or more events are detected within the radius — a swarm is itself a signal even when no single quake is large. Depth is reported but does not currently factor into the severity calculation; shallow quakes (under 10 km) cause more surface damage at equal magnitude, which operators should treat as a contextual escalation when reading the detail card.
Use cases for event security
- Pre-show rigging revalidation. A M4.5+ within 50 km of the venue in the 24 hours before doors triggers a structural engineer walkthrough of all temporary scaffolding, LED walls, and rigging, with sign-off documented to the venue's risk file.
- Aftershock-window decisions. USGS aftershock probability tables show 80% of M6.0+ mainshocks produce a M5.0+ aftershock within 7 days. When the mainshock-aftershock window overlaps with the event date, doors decisions should be made with the venue's structural engineer in the loop.
- Crowd-flow contingency. Mid-show seismic events change everyone's behavior — staff need a pre-rehearsed announcement, evacuation routes, and rally points. SignalGuard provides the trigger; your operational plan does the rest.
Pairs well with
- Weather monitoring — combined seismic + weather days are the worst-case for outdoor infrastructure.
- Traffic monitoring — large quakes generate route-closure cascades that affect egress.
- Wildfire smoke monitoring — California venues face overlapping seismic + wildfire seasons.
Premium upgrade path
USGS is the authoritative free source — paid alternatives mostly republish USGS data with added decoration. For specialized event needs, ShakeAlert (operated by USGS) offers earthquake early warning for the West Coast US with sub-second latency between detection and alert. Integration is regulated and varies by state. International event operators in Japan benefit from JMA's earthquake early warning feed; for Mediterranean venues, EMSC's last-quakes feed has tighter regional latency than the USGS global aggregator. See the Integrations page.
Frequently asked questions
Does SignalGuard track earthquakes globally? Yes — USGS aggregates international seismic networks, and our radius filter applies to any global coordinate. Coverage and detection thresholds vary by region; M2.5+ is typically reliable globally, M2.0+ in well-instrumented zones (California, Japan, Italy).
What earthquake magnitude should I worry about for an outdoor event? M4.0+ within 25 km typically causes light shaking that draws crowd attention but rarely structural damage. M5.0+ within 50 km should trigger a rigging inspection. M6.0+ within 100 km is the threshold where most venues evacuate as a precaution.
Does SignalGuard provide earthquake early warning? Not directly — the USGS summary feed is post-detection. For pre-event ShakeAlert integration on the US West Coast, BYOK ShakeAlert via Enterprise.
What if my venue is in a non-seismic region?
The signal still runs and reports none if no events meet the radius. There's no operational cost to having it on for low-seismic-risk events.
Can I configure the radius and magnitude thresholds? Yes — Enterprise customers can override the defaults per event. See SignalGuard docs.
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