Event Number 2863

M3.8 km SE of San Ramon, CA - 2025/12/20 03:49:22 37.749 -121.938 M3.8 9.3 5 km SE of San Ramon, CA at 2025/12/20 03:49:22 UTC / 2025/12/19 19:49:22 PDT

Error Map and Stations Used to Locate Event

Errors from USGS Location and Magnitude:

EQPROC = 3.7km (2.3 mi)
HYPO2K = 4.5km (2.8 mi) Magnitude = 0.1

USGS Report:

Date       Time       Lat    Lon      Mag    Depth                Location   
-----------------------------------------------------------------------------------
2025/12/20 03:49:22  37.749 -121.938  M3.8   9.3 5 km SE of San Ramon, CA

EQPROC Summary:

2863 2025Dec20  349 23.60  37.7425 -121.9796  3.00 0.11 23.4 60.1 149  9
GLFBZ SHZ PN 01 2025Dec20  349 30.50 P ?1  36.4  -0.00
RE9A7 EHZ AM 00 2025Dec20  349 32.77 P ?1  49.8  -0.00
ADUB1 SHZ PN 01 2025Dec20  349 33.89 P ?3  55.0   0.23
LCGPZ SHZ PN 01 2025Dec20  349 35.82 S D2  35.7   0.54
ATZ   SHZ PN 01 2025Dec20  349 38.81 P D1  85.2   0.03
B057  EHZ PB -- 2025Dec20  349 34.05 P U0  60.6  -0.56
B054  EHZ PB -- 2025Dec20  349 28.30 P U0  23.4  -0.00
B058  EHZ PB -- 2025Dec20  349 41.99 P D3 110.5  -0.54
B073  EHZ PB -- 2025Dec20  350  4.76 PgD3 239.8   3.35

HYPO2K Report:

 YEAR MO DA  --ORIGIN--  --LAT N-  --LON W--  DEPTH-M RMS   ERH   ERZ  XMAG1 FMAG1 PMAG GEOID-DEP
 2025-12-20  0349 23.91  37 45.297 121W59.340  0.80  0.14  0.86 13.34        3.69  3.69E    0.79
                                                                                          SOURCE
 NSTA NPHS  DMIN MODEL GAP ITR NFM NWR NWS NVR REMRKS-AVH  N.XMG-XMMAD-T   N.FMG-FMMAD-T  L F X
    8    8  21.9  Emb  151   6   5   6   0   8      -                          5  0.47 E  W W  

 XMAG2-N.XMG2-XMMAD-T-S  FMAG2-N.FMG2-FMMAD-T-S  PREF.MAG-N.PMAG-PRMAD-T DEPDAT NS ZT TYP
                                                     3.69      5  0.47 E     11  5  M CRH
 REGION=                          

 STA NET COM L CR DIST AZM  AN P/S WT   SEC (TOBS -TCAL -DLY  =RES)  WT   SR  INFO  CAL  DUR-W-FMAG-T -AMP-U-PER-W-XMAG-T DE
 B054 PB EHZ -- A 21.9 303  27  PU    28.30  4.39  4.24 0.00  0.15  1.33  W  0.997 0.00  103   3.59 E                        
 GLFBZPN SHZ 01 A 37.3 203  27  P  1  30.50  6.59  6.74 0.00 -0.15  1.00  W  0.530 0.00  103 1 3.69 E                        
 RE9A7AM EHZ 00 A 50.6  94  27  P  1  32.77  8.86  8.91 0.00 -0.05  1.00  W  0.957 0.00 85.0 4 3.53XE                        
 ADUB1PN SHZ 01 A 56.3 179  27  P  3  33.89  9.98  9.84 0.00  0.14  0.33  W  0.053 0.00  190   4.31 E                        
 B057 PB EHZ -- A 59.0 301  27  PU    34.05 10.14 10.28 0.00 -0.14  1.33  W  0.995 0.00 89.0   3.58 E                        
 ATZ  PN SHZ 01 A 86.6 174  27  PD 1  38.81 14.90 14.76 0.00  0.14  1.00  W  0.465 0.00  332 2 4.88 E                        
 B058 PB EHZ -- A112.0 161  27  PD 3  41.99 18.08 18.90 0.00 -0.82* 0.00  W  0.000 0.00 1.00 4                               
 B073 PB EHZ -- A242.0 145  20  PD 3  64.76 40.85 37.66 0.00  3.19* 0.00  W  0.000 0.00 1.00 4                               

Event Files: December 2025