Early-est:     Samoa Islands Region    2026.06.23-07:11:15.55    q:C      mb:4.8*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1782198678400.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1782198678400.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1782198678400.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: 4.8* [15]    Mwp: - [0]    Mwpd: - [0]
Region: Samoa Islands Region
Origin Time: 2026.06.23-07:11:15.55 UTC
Hypocenter: lat: -16.52°  lon: -171.77°  [+/-39km]    depth: 15km  [+/-33km]
Location Quality: qualityCode:  C     stdErr: 3.0s   assocPhases: 59   usedPhases: 38
minDist: 2.6°   maxDist: 152.7°   AzGap: 96°   2ndAzGap: 135°   atten: -1.22 [+/-0.39]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 26km   maxHorUnc: 39km   azMaxHorUnc: 130°
68%ConfEllipsoid:   semiMajorAxisLength: 51km   majorAxisAzimuth: 309°   majorAxisPlunge: 19°   semiIntermediateAxisLength: 33km   intermediateAxisAzimuth: 216°   intermediateAxisPlunge: 9°   semiMinorAxisLength: 30km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [6]    Td: -s [0]    Td*T50Ex: - [0]    To: 1.9s [6]
Closest plate boundaries:
   Tonga / Pacific [subduction zone]: distance: ~60km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (60km)
 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.1782198678400.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 88°   dip: 20°   rake: -55°
Nodal Plane 2: strike: 231°   dip: 74°   rake: -102°
Quality: azimuthalGap: -1°   stationPolarityCount: 16   misfitWeightCount: 4.7   misfit: 0.07   stationDistributionRatio: 0.59   meanDistP: 42.0   meanDistT: 45.4   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1782198678400.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.1782198678400.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 347°   dip: 39°   rake: -128°
Nodal Plane 2: strike: 212°   dip: 60°   rake: -64°
Quality: azimuthalGap: 98°   stationPolarityCount: 16   misfit: 0.20   stationDistributionRatio: 0.75   rmsAngDiffAccPref: 41.27   fracAcc30degPref: 0.44   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1782198678400.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1782198678400
Event info last updated: 2026.06.23-08:10:00 UTC
Event first association/location: 2026.06.23-07:27:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA