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Max Est. MMI

M4.7 earthquake · shaking intensity by town 3 km WSW of Brawley, CA

Magnitude4.7
Depth14.5 km
Time 2026-05-10T07:10:21.250000Z UTC: 2026-05-10T07:10:21.250000Z
USGS ID ci41461608
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)
Brawley
CA 		760 227
Westmorland
CA 		760 211
Calipatria
CA 		760 218
Imperial
CA 		760 227

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 -0.47 0.44 0.64
BSSA14 -0.22 0.39 0.45
CY14 -0.36 0.44 0.57
CB14 -0.43 0.45 0.62
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)
Airport Hangar (NP.5060) 0.4142 Severe(VIII) 19.942 Very Strong(VII)
Imperial (CI.IMP) 0.1348 Strong(VI) 2.897 Light(IV)
Calipatria 2 (CI.CLI2) 0.0966 Moderate(V) 3.236 Light(IV)
Westmorland (CE.11369) 0.0770 Moderate(V) 2.437 Light(IV)
Desert Research Extended Center (CI.DRE) 0.0344 Light(IV) 1.808 Light(IV)
Salton Sea Wildlife (SSW) (NP.5062) 0.0335 Light(IV) 1.154 Weak(III)
El Centro Array 1, Borchard Ranches (NP.5056) 0.0191 Weak(III) 1.042 Weak(III)
Bonds Corner, Omlin Residence (NP.5054) 0.0171 Weak(III) 0.711 Weak(III)
Ocotillo Community Park (CI.OCP) 0.0166 Weak(III) 0.454 Weak(III)
Cook Ranch 2 (CI.COK2) 0.0154 Weak(III) 0.679 Weak(III)
Coachella (CI.COA) 0.0146 Weak(III) 0.419 Weak(III)
Schaffner Ranch (CI.SNR) 0.0144 Weak(III) 1.318 Light(IV)
El Centro (CI.ELO) 0.0130 Weak(III) 0.670 Weak(III)
Elmore's Ranch (CI.ERR) 0.0100 Weak(III) 0.524 Weak(III)
Fire Station (NP.5053) 0.0094 Weak(III) 0.396 Weak(III)
CA:Pine Valley;FS (NP.5491) 0.0087 Weak(III) 0.307 Weak(III)
Sam W. Stewart (CI.SWS) 0.0083 Weak(III) 0.259 Weak(II)
Niland (CE.11698) 0.0080 Weak(III) 0.433 Weak(III)
Rock Hill (CI.RXH) 0.0080 Weak(III) 0.376 Weak(III)
CA:El Centro;ECA11 McCabe Sch (NP.5058) 0.0080 Weak(III) 0.537 Weak(III)
Campo (CE.02496) 0.0073 Weak(III) 0.170 Weak(II)
Wister Waterfowl (CI.WWF) 0.0073 Weak(III) 0.288 Weak(III)
UABC Campus Mexicali (BC.UABX) 0.0070 Weak(III) 0.310 Weak(III)
Ejido Yucatan (BC.YUC2X) 0.0052 Weak(II) 0.229 Weak(II)
East Mesa (CI.EMS) 0.0047 Weak(II) 0.228 Weak(II)
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

4 sites
Location MMI Description
Brawley
CA 		Moderate(V)
Westmorland
CA 		Light(IV)
Calipatria
CA 		Light(IV)
Imperial
CA 		Light(IV)

Seismic Station Observed MMI

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

6 stations
Station MMI Description
Airport Hangar (NP.5060) Very Strong(VII)
Calipatria 2 (CI.CLI2) Light(IV)
Imperial (CI.IMP) Light(IV)
Westmorland (CE.11369) Light(IV)
Desert Research Extended Center (CI.DRE) Light(IV)
Schaffner Ranch (CI.SNR) Light(IV)