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II

Max Est. MMI

20 km W of Preston, Nevada

Magnitude4.4
Depth? km
Time 2026-09-27T08:54:07.495000Z UTC: 2026-09-27T08:54:07.495000Z
USGS ID nn00924954
ShakeMap View USGS ↗

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 +0.27 0.41 0.46
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)