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II

Max Est. MMI

6 km NW of Pinnacles, CA

Magnitude3.6
Depth2.2 km
Time 2026-08-02T12:36:57.380000Z UTC: 2026-08-02T12:36:57.380000Z
USGS ID nc75410062
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Ground Shaking Intensities — Interpolated ShakeMap MMI

3 sites
Location MMI Description
Soledad
CA
Weak(II)
Gonzales
CA
Weak(II)
Greenfield
CA
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
Mount Johnson (NC.BJOB) Weak(III)
Panoche Road (NC.BPA) Weak(II)
Big Mountain #3 (NC.BBGB) Weak(III)

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)
Soledad
CA
760 231
Gonzales
CA
760 228
Greenfield
CA
760 294

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 +0.11 0.37 0.39
BSSA14 +0.11 0.37 0.39
CY14 +0.11 0.37 0.39
CB14 +0.11 0.36 0.37
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)
Mount Johnson (NC.BJOB) 0.0174 Weak(III) 0.398 Weak(III)
Shirttail Gulch (NC.BSG) 0.0143 Weak(II) 0.157 Weak(II)
Big Mountain #3 (NC.BBGB) 0.0070 Not felt(I) 0.223 Weak(II)
Crazy Canyon #3 (NC.PCC) 0.0048 Not felt(I) 0.165 Weak(II)
Chualar Canyon, Santa Cruz, CA, USA (BK.SCZ) 0.0032 Not felt(I) 0.060 Weak(II)
Juan Fiesta (NC.BJF) 0.0027 Not felt(I) 0.065 Weak(II)
Panoche Road (NC.BPA) 0.0024 Not felt(I) 0.071 Weak(II)
Cienega Road (NC.BCGB) 0.0022 Not felt(I) 0.030 Not felt(I)
Pinnacle Vineyards (NC.BPV) 0.0021 Not felt(I) 0.138 Weak(II)
The Indians Road (NC.BTI) 0.0020 Not felt(I) 0.041 Not felt(I)
Lonoak Road 2 (NC.PLOB) 0.0019 Not felt(I) 0.058 Weak(II)
Topo Valley (NC.BTV) 0.0018 Not felt(I) 0.056 Not felt(I)
Palo Escrito (NC.BPE) 0.0016 Not felt(I) 0.035 Not felt(I)
Ponciano Ridge (NC.BPRB) 0.0015 Not felt(I) 0.042 Not felt(I)
Salinas Radio Site #2 (NC.BSR) 0.0014 Not felt(I) 0.033 Not felt(I)
Hahn Winery (NC.BHW) 0.0013 Not felt(I) 0.049 Not felt(I)
Chews Ridge (NC.BCWB) 0.0012 Not felt(I) 0.031 Not felt(I)
Williams Hill (NC.PWH) 0.0012 Not felt(I) 0.031 Not felt(I)
Landels-Hill Big Creek Reserve, Lucia, CA (BK.LAND) 0.0012 Not felt(I) 0.042 Not felt(I)
Anderson Peak (NC.BAPB) 0.0011 Not felt(I) 0.020 Not felt(I)
Bitterwater Creek (NC.PBC) 0.0009 Not felt(I) 0.028 Not felt(I)
Calera Canyon (NC.BCC) 0.0009 Not felt(I) 0.026 Not felt(I)
San Andreas Geophysical Obs., Hollister, CA, USA (BK.SAO) 0.0008 Not felt(I) 0.011 Not felt(I)
Monterey #4 (NC.HMOB) 0.0008 Not felt(I) 0.025 Not felt(I)
San Ardo (NC.PSAB) 0.0007 Not felt(I) 0.013 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.