Early-est:     South of Tonga Islands    2025.12.09-21:00:17.17    q:B      mb:5.1    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1765314022506.mech.fmamp_polarity.thumb.jpg     hash:./hypo.1765314022506.mech.hash.thumb.jpg     fmamp_amp_aref:./hypo.1765314022506.mech.fmamp_amp_aref.thumb.jpg     fmamp_amp_mwp:./hypo.1765314022506.mech.fmamp_amp_mwp.thumb.jpg

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

Earthquake Details:
Magnitude: mb: 5.1 [52]    Mwp: 5.8X [2]    Mwpd: 7.5Xinv [1]
Region: South of Tonga Islands
Origin Time: 2025.12.09-21:00:17.17 UTC
Hypocenter: lat: -26.92°  lon: -175.75°  [+/-23km]    depth: 16km  [+/-63km]
Location Quality: qualityCode:  B     stdErr: 2.4s   assocPhases: 107   usedPhases: 85
minDist: 9.5°   maxDist: 155.2°   AzGap: 61°   2ndAzGap: 83°   atten: -0.93 [+/-0.25]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 23km   azMaxHorUnc: 23°
68%ConfEllipsoid:   semiMajorAxisLength: 67km   majorAxisAzimuth: 27°   majorAxisPlunge: 69°   semiIntermediateAxisLength: 18km   intermediateAxisAzimuth: 159°   intermediateAxisPlunge: 15°   semiMinorAxisLength: 15km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [27]    Td: 4.8Xs [3]    Td*T50Ex: - [0]    To: 5.1s [21]
Closest plate boundaries:
   Kermadec / Pacific [subduction zone]: distance: ~40km
Subduction geometry:    Zone: Kermadec-Tonga    Slab depth at epicenter: 13km
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (40km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       16km
       16km
       16km
Slab depth at epicenter:
       13km
       -
       -
./hypo.1765314022506.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 68°   dip: 8°   rake: 171°
Nodal Plane 2: strike: 167°   dip: 89°   rake: 82°
Quality: azimuthalGap: -1°   stationPolarityCount: 79   misfitWeightCount: 8.9   misfit: 0.19   stationDistributionRatio: 0.47   meanDistP: 29.9   meanDistT: 30.2   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1765314022506.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 354°   dip: 14°   rake: 106°
Nodal Plane 2: strike: 157°   dip: 76°   rake: 86°
Quality: azimuthalGap: 60°   stationPolarityCount: 79   misfit: 0.32   stationDistributionRatio: 0.48   rmsAngDiffAccPref: 34.53   fracAcc30degPref: 0.50   qualityCode: D
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1765314022506.mech.hash.mechanism.jpg
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: nan°
Nodal Plane 2: strike: nan°   dip: nan°   rake: nan°
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/_amp_aref
./hypo.1765314022506.mech.fmamp_amp_aref.mechanism.jpg
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: nan°
Nodal Plane 2: strike: nan°   dip: nan°   rake: nan°
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/_amp_mwp
./hypo.1765314022506.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1765314022506
Event info last updated: 2025.12.09-22:00:47 UTC
Event first association/location: 2025.12.09-21:07:35 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI