Early-est:     Virgin Islands    2026.03.31-21:15:37.11    q:C      mb:4.9*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1774991738476.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1774991738476.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1774991738476.mech.hash.thumb.jpg

Automatic solution - this event has not been reviewed by a seismologist
Automatically determined event information may be incorrect!

Earthquake Details:
Magnitude: mb: 4.9* [10]    Mwp: - [0]    Mwpd: - [0]
Region: Virgin Islands
Origin Time: 2026.03.31-21:15:37.11 UTC
Hypocenter: lat: 19.01°  lon: -64.91°  [+/-15km]    depth: 15km  [+/-13km]
Location Quality: qualityCode:  C     stdErr: 1.6s   assocPhases: 23   usedPhases: 15
minDist: 1.5°   maxDist: 161.8°   AzGap: 104°   2ndAzGap: 150°   atten: -1.96 [+/-0.22]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 10km   maxHorUnc: 15km   azMaxHorUnc: 8°
68%ConfEllipsoid:   semiMajorAxisLength: 18km   majorAxisAzimuth: 187°   majorAxisPlunge: 5°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 90°   intermediateAxisPlunge: 53°   semiMinorAxisLength: 12km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [9]    Td: 1.0Xs [1]    Td*T50Ex: - [0]    To: 34.9s [8]
Closest plate boundaries:
   Caribbean - North America [oceanic transform fault]: distance: ~90km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 no
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       15km
       15km
       15km
Slab depth at epicenter:
       n/a
       -
       -
Tsunami and Rupture predictions (TEST!): No prediction: Event too small (Mwp<7.0) or too few Mwp readings (N<20)
./hypo.1774991738476.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 177°   dip: 12°   rake: -111°
Nodal Plane 2: strike: 19°   dip: 78°   rake: -86°
Quality: azimuthalGap: -1°   stationPolarityCount: 9   misfitWeightCount: 4.0   misfit: 0.02   stationDistributionRatio: 0.51   meanDistP: 43.4   meanDistT: 50.0   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1774991738476.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (FMAMP_POLARITY_WAVEFORM):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: 0°
Nodal Plane 2: strike: 270°   dip: 90°   rake: 90°
Quality: azimuthalGap: -1°   stationPolarityCount: 0   misfitWeightCount: -1.0   misfit: -1.00   stationDistributionRatio: -1.00   meanDistP: -1.0   meanDistT: -1.0   qualityCode: X
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity_waveform
./hypo.1774991738476.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (No solution available)
Nodal Plane 1: strike: 999°   dip: 99°   rake: 999°
Nodal Plane 2: strike: 324°   dip: 13°   rake: 135°
Quality: azimuthalGap: 161°   stationPolarityCount: 9   misfit: 0.99   stationDistributionRatio: 0.67   rmsAngDiffAccPref: 35.32   fracAcc30degPref: 0.00   qualityCode: E
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1774991738476.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1774991738476
Event info last updated: 2026.03.31-22:14:03 UTC
Event first association/location: 2026.03.31-21:26:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA