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II

Max Est. MMI

15 km NW of Pinnacles, CA

Magnitude3.7
Depth12.0 km
Time 2026-07-09T14:49:17.930000Z UTC: 2026-07-09T14:49:17.930000Z
USGS ID nc75392631
ShakeMap View USGS ↗

Ground Shaking Intensities — Interpolated ShakeMap MMI

3 sites
Location MMI Description
Gonzales
CA
Weak(II)
Ridgemark
CA
Weak(II)
Soledad
CA
Weak(II)

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) Light(IV)
Pinnacle Vineyards (NC.BPV) Weak(III)
Cienega Road (NC.BCGB) 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)
Gonzales
CA
760 228
Ridgemark
CA
760 380
Soledad
CA
760 231

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 +0.15 0.42 0.45
BSSA14 +0.14 0.39 0.42
CY14 +0.14 0.39 0.41
CB14 +0.14 0.37 0.40
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) 0.0507 Light(IV) 1.024 Light(IV)
Shirttail Gulch (NC.BSG) 0.0175 Weak(III) 0.248 Weak(II)
Cienega Road (NC.BCGB) 0.0108 Weak(II) 0.268 Weak(II)
Panoche Road (NC.BPA) 0.0083 Weak(II) 0.256 Weak(II)
Salinas Radio Site #2 (NC.BSR) 0.0064 Not felt(I) 0.094 Weak(II)
Pinnacle Vineyards (NC.BPV) 0.0063 Not felt(I) 0.209 Weak(II)
Ponciano Ridge (NC.BPRB) 0.0051 Not felt(I) 0.108 Weak(II)
Monterey #4 (NC.HMOB) 0.0041 Not felt(I) 0.080 Weak(II)
Hastings 2 (BK.HAS2) 0.0037 Not felt(I) 0.092 Weak(II)
Crazy Canyon #3 (NC.PCC) 0.0036 Not felt(I) 0.085 Weak(II)
Big Mountain #3 (NC.BBGB) 0.0034 Not felt(I) 0.117 Weak(II)
Juan Fiesta (NC.BJF) 0.0034 Not felt(I) 0.107 Weak(II)
Palo Escrito (NC.BPE) 0.0033 Not felt(I) 0.092 Weak(II)
Landels-Hill Big Creek Reserve, Lucia, CA (BK.LAND) 0.0031 Not felt(I) 0.086 Weak(II)
Strathearn Ranch; UC Natural Reserve (BK.STRA) 0.0029 Not felt(I) 0.094 Weak(II)
Chualar Canyon, Santa Cruz, CA, USA (BK.SCZ) 0.0029 Not felt(I) 0.072 Weak(II)
San Andreas Geophysical Obs., Hollister, CA, USA (BK.SAO) 0.0028 Not felt(I) 0.044 Not felt(I)
Anderson Peak (NC.BAPB) 0.0027 Not felt(I) 0.059 Weak(II)
Calera Canyon (NC.BCC) 0.0027 Not felt(I) 0.052 Not felt(I)
Chews Ridge (NC.BCWB) 0.0025 Not felt(I) 0.056 Not felt(I)
Brookhollow Lane (NC.HBH) 0.0023 Not felt(I) 0.085 Weak(II)
Hahn Winery (NC.BHW) 0.0022 Not felt(I) 0.074 Weak(II)
Palo Corona Regional Park (NC.BPL) 0.0017 Not felt(I) 0.048 Not felt(I)
San Benito Historical Park (NC.HHP) 0.0017 Not felt(I) 0.056 Not felt(I)
Fort Ord Natural Reserve, Marina, CA (BK.FORD) 0.0016 Not felt(I) 0.037 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.