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II

Max Est. MMI

20 km W of Preston, Nevada

Magnitude4.1
Depth6.0 km
Time 2026-09-27T08:54:07.495000Z UTC: 2026-09-27T08:54:07.495000Z
USGS ID nn00924954
ShakeMap View USGS ↗

Shaking Animations

Simulated bowling pin shaking at each city’s intensity level. Videos appear as they finish rendering. The ground motion behind each video is under Ground Motion Records.

6 sites
Location Type Intensity at site Animation Ground motion
Decay: Las Vegas direction Decay · Kitchen Simulated Weak(III) USGS ShakeMap, 5 km site Download Produced 2026-09-28T14:50:35.817713Z Seismogram of the ground motion behind this animation Data files
Decay: Las Vegas direction Decay · Tabletop Simulated Weak(III) USGS ShakeMap, 5 km site Download Produced 2026-09-28T05:51:03.993758Z Seismogram of the ground motion behind this animation Data files
Willow Creek Ranch, Ely, NV, USA - NN reactivation Station · Tabletop Observed Weak(II) station record Download Produced 2026-09-28T06:37:07.230549Z
Willow Creek Ranch, Ely, NV, USA - NN reactivation Station · Kitchen Observed Weak(II) station record Download Produced 2026-09-28T23:46:16.983301Z
Ely City · Tabletop Simulated Weak(II) USGS ShakeMap Download Produced 2026-09-28T06:50:46.247439Z Seismogram of the ground motion behind this animation Data files
Ely City · Kitchen Simulated Weak(II) USGS ShakeMap

Ground Motion Records

The shaking each animation was drawn from: acceleration, velocity and displacement in three directions. The shaded band marks the part the animation shows.

Download all (zip)

City · Simulated — Ely, NV

Used by the Tabletop video

A physics-based simulation of this earthquake (SCEC Broadband Platform) at this site: one realization, not an average.

Acceleration, velocity and displacement seismograms for city animation
Site PGA (g) PGV (cm/s) PGD (cm) Data files
Ely, NV 0.0029 0.09 0.00 Acceleration · Velocity · Displacement

Peak values are horizontal (the larger of north–south and east–west) over the whole record. Time zero: rupture origin time (simulation time 0).

Decay · Simulated — 5 km from the epicenter, 50 km from the epicenter, 100 km from the epicenter

Used by the Kitchen video and Tabletop video

A physics-based simulation of this earthquake (SCEC Broadband Platform) at this site: one realization, not an average.

Acceleration, velocity and displacement seismograms for decay animation
Site PGA (g) PGV (cm/s) PGD (cm) Data files
5 km from the epicenter 0.0436 1.01 0.04 Acceleration · Velocity · Displacement
50 km from the epicenter 0.0025 0.08 0.00 Acceleration · Velocity · Displacement
100 km from the epicenter 0.0009 0.03 0.00 Acceleration · Velocity · Displacement

Peak values are horizontal (the larger of north–south and east–west) over the whole record. Time zero: rupture origin time (simulation time 0).

About these files

Each file is plain text in the SCEC Broadband Platform layout. Lines starting with # are a header describing the earthquake, the site, where the motion came from, how it was processed, its peak values, and which part the animation shows. Then come four columns: time (s), north–south, east–west, and up–down. North–south comes before east–west.

Units: acceleration in cm/s², velocity in cm/s, displacement in cm. The zip also contains the plots and a README.

To read a file in Python: t, ns, ew, ud = numpy.loadtxt("file.acc.bbp", comments="#", unpack=True). A spreadsheet can open it as whitespace-delimited text.

These records explain what the animations show. A single simulation, one station’s record, or a synthetic scaled to one value is not an engineering estimate of ground motion at a site.

Engineering Ground Motion Parameters

GMPE predictions provide an independent check on the ShakeMap interpolated intensities above. ShakeMap relies on seismic station recordings; in areas with sparse station coverage — or for large teleseismic events and earthquakes outside dense West Coast networks — ShakeMap MMI can be inaccurate. A significant difference between ShakeMap and GMPE estimates is a signal that the ShakeMap result should be treated as preliminary. Also includes site Vs30 values and raw ground motion parameters (PGA/PGV).

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Est. Vs30 Values

Estimated shear-wave velocity in the upper 30 m used in GMPE calculations. Ref. column shows the 760 m/s rock-site reference for comparison.

Location Ref. (760 m/s) Est. Vs30 (m/s)
Ely
NV
760 569
McGill
NV
760 533
Eureka
NV
760 563

MMI vs Distance — Default Vs30 (760 m/s)

All methods using the 760 m/s rock-site reference. ShakeMap values are independent of Vs30.

MMI vs distance — default Vs30

MMI vs Distance — Est. Vs30

GMPEs use the Est. Vs30 values shown in the table above. ShakeMap values are independent of Vs30.

MMI vs distance — Est. Vs30

GMPE Residual — Observed − Predicted MMI

Signed residual at each seismic station. Positive values mean the GMPE underestimated shaking; negative values mean it overestimated. The dashed line at zero indicates perfect agreement.

GMPE residual plot

GMPE Predicted vs. Observed MMI at Seismic Stations

Each point is one seismic station. Points on the dashed 1:1 line indicate perfect agreement; above the line = GMPE underestimated shaking; below = overestimated.

GMPE predicted vs observed scatter

GMPE Performance — Station Observations

Statistics computed by comparing each GMPE's predicted MMI against ShakeMap observed MMI at seismic stations. Bias = mean(observed − predicted). Lower RMSE indicates better overall agreement with instrumental measurements.

GMPE Bias Sigma RMSE
ASK14 +0.28 0.44 0.49
BSSA14 +0.28 0.44 0.49
CY14 +0.28 0.44 0.49
CB14 +0.28 0.44 0.49
Bias > 0: GMPE underestimated shaking at stations. Bias < 0: GMPE overestimated shaking.

Peak Ground Motion — Seismic Station Observations

Recorded PGA and PGV at seismic stations, sorted by highest PGA. Top 25 stations shown. MMI (PGA) and MMI (PGV) are independent conversions via Worden et al. (2012) GMICE.

Station PGA (g) MMI (PGA) PGV (cm/s) MMI (PGV)
Willow Creek Ranch, Ely, NV, USA - NN reactivation (NN.Q12A) 0.0026 Not felt(I) 0.057 Not felt(I)
Pony Springs, Pioche, NV, USA (NN.R12A) 0.0011 Not felt(I) 0.032 Not felt(I)
Pine Springs, UT (UU.PSUT) 0.0005 Not felt(I) 0.021 Not felt(I)
Rachel, NV, USA - NN reactivation (NN.S11A) 0.0004 Not felt(I) 0.018 Not felt(I)
Troy Canyon, Currant, NV, USA (NN.R11B) 0.0003 Not felt(I) — —
Pioche, NV, USA - NN reactivation (NN.PIO) 0.0003 Not felt(I) 0.010 Not felt(I)
Source: USGS ShakeMap station recordings (view ShakeMap). PGA in g (fraction of gravitational acceleration); PGV in cm/s. The observed MMI shown on the map uses ShakeMap's reported instrumental intensity where available, or max(MMI from PGA, MMI from PGV) otherwise.

Ground Shaking Intensities — Interpolated ShakeMap MMI

3 sites
Location MMI Description
Ely
NV
Weak(II)
McGill
NV
Not felt(I)
Eureka
NV
Not felt(I)

Seismic Station Observed MMI

MMI values are derived directly from observed ground motion measurements at seismic stations and are not spatially interpolated.

3 stations
Station MMI Description
Willow Creek Ranch, Ely, NV, USA - NN reactivation (NN.Q12A) Weak(II)
Troy Canyon, Currant, NV, USA (NN.R11B) Not felt(I)
Pony Springs, Pioche, NV, USA (NN.R12A) Not felt(I)