Max Est. MMI
11 km N of Covelo, CA
Ground Shaking Intensities — Interpolated ShakeMap MMI
3 sites| Location | MMI Description |
|---|---|
|
Covelo
CA |
Weak(III) |
|
Laytonville
CA |
Weak(II) |
|
Brooktrails
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.
| Station | MMI Description |
|---|---|
| Round Valley Indian Tribe, Mendocino County, CA (BK.RVIT) | Weak(III) |
| Long Ridge (NC.KLR) | Weak(II) |
| Iron Peak (NC.KIP) | Weak(II) |
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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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).
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) |
|---|---|---|
|
Covelo
CA |
760 | 294 |
|
Laytonville
CA |
760 | 352 |
|
Brooktrails
CA |
760 | 468 |
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 — Est. Vs30
GMPEs use the Est. Vs30 values shown in the table above. ShakeMap values are independent of 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 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 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 | +0.20 | 0.43 | 0.48 |
| BSSA14 | +0.20 | 0.43 | 0.47 |
| CY14 | +0.19 | 0.41 | 0.46 |
| CB14 | +0.19 | 0.41 | 0.45 |
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) |
|---|---|---|---|---|
| Round Valley Indian Tribe, Mendocino County, CA (BK.RVIT) | 0.0155 | Weak(III) | 0.971 | Light(IV) |
| Sherwood Rancheria area, Willits (BK.SHWD) | 0.0044 | Not felt(I) | 0.226 | Weak(II) |
| Iron Peak (NC.KIP) | 0.0043 | Not felt(I) | 0.199 | Weak(II) |
| Etsel Ridge (BK.ETSL) | 0.0026 | Not felt(I) | 0.209 | Weak(II) |
| Usal Creek (BK.USAL) | 0.0022 | Not felt(I) | 0.134 | Weak(II) |
| Hull Mountain (BK.HULL) | 0.0021 | Not felt(I) | 0.142 | Weak(II) |
| Hales Grove, Mendocino, CA (BK.HALS) | 0.0019 | Not felt(I) | 0.091 | Weak(II) |
| Woodlands Fire Station, Mendocino, CA (BK.MNDO) | 0.0018 | Not felt(I) | 0.132 | Weak(II) |
| Navarro Ridge (NC.GNR) | 0.0017 | Not felt(I) | 0.117 | Weak(II) |
| Long Ridge (NC.KLR) | 0.0015 | Not felt(I) | 0.081 | Weak(II) |
| Orr Springs (BK.ORRS) | 0.0015 | Not felt(I) | 0.134 | Weak(II) |
| Sproul Creek (BK.SPRL) | 0.0014 | Not felt(I) | 0.091 | Weak(II) |
| Garberville CALFire station (NP.1591) | 0.0013 | Not felt(I) | 0.092 | Weak(II) |
| Jewett Creek (BK.JEWT) | 0.0012 | Not felt(I) | 0.081 | Weak(II) |
| Red Bank (NC.LRB) | 0.0011 | Not felt(I) | 0.057 | Not felt(I) |
| Hoaglin-Zenia Elementary School (NC.KZE) | 0.0010 | Not felt(I) | 0.091 | Weak(II) |
| Black Lassic (BK.BLAS) | 0.0009 | Not felt(I) | 0.052 | Not felt(I) |
| Barra Winery, Redwood Valley, CA (BK.BARR) | 0.0009 | Not felt(I) | 0.062 | Weak(II) |
| Bevans Ridge (BK.BEVN) | 0.0009 | Not felt(I) | 0.058 | Weak(II) |
| Van Arsdale (NC.GVA) | 0.0009 | Not felt(I) | 0.053 | Not felt(I) |
| Paradise Ridge (BK.PRDS) | 0.0008 | Not felt(I) | 0.064 | Weak(II) |
| Bell Springs #3 (NC.KBSB) | 0.0008 | Not felt(I) | 0.055 | Not felt(I) |
| Big Hunter Mountain, Trinity County (BK.HUNT) | 0.0008 | Not felt(I) | 0.040 | Not felt(I) |
| Pettyjohn Place, Tehama County, CA (BK.PETY) | 0.0007 | Not felt(I) | 0.031 | Not felt(I) |
| Briceland Vineyard, Redway, CA (BK.BRIC) | 0.0007 | Not felt(I) | 0.051 | Not felt(I) |