Early-est:     Tonga Islands    2026.10.12-04:38:12.21    q:A      mb:5.2    Mwp:5.5    Mwpd:-    Td*T50Ex:0.1     fmamp_polarity:     hash:     fmamp_amp_aref:     fmamp_amp_mwp:

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

Earthquake Details: Magnitude: mb: 5.2 [71]    Mwp: 5.5 [10]    Mwpd: 5.8Xinv [5] Region: Tonga Islands Origin Time: 2026.10.12-04:38:12.21 UTC Hypocenter: lat: -18.71°  lon: -174.89°  [+/-17km]    depth: 184km  [+/-24km] Location Quality: qualityCode:  A     stdErr: 1.5s   assocPhases: 185   usedPhases: 150 minDist: 4.7°   maxDist: 175.9°   AzGap: 41°   2ndAzGap: 45°   atten: -1.46 [+/-0.17] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 15km   maxHorUnc: 17km   azMaxHorUnc: 73° 68%ConfEllipsoid:   semiMajorAxisLength: 26km   majorAxisAzimuth: 56°   majorAxisPlunge: 58°   semiIntermediateAxisLength: 19km   intermediateAxisAzimuth: 313°   intermediateAxisPlunge: 8°   semiMinorAxisLength: 17km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.0 [53]    Td: 1.7s [11]    Td*T50Ex: 0.1 [11]    To: 1.8s [46] Closest plate boundaries:    Tonga - Niuafo'ou [continental rift boundary]: distance: ~10km    Niuafo'ou - Australia [oceanic transform fault]: distance: ~140km    Tonga - Australia [oceanic spreading ridge]: distance: ~140km    Tonga / Pacific [subduction zone]: distance: ~220km Subduction geometry:    Zone: Kermadec-Tonga    Slab depth at epicenter: 134km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (220km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    0.1    0.1    0.1 Td*To:      3.1      3.1      3.1 Mwp magnitude:        5.5        5.5        5.5 Hypocenter depth:        184km        184km        184km Slab depth at epicenter:        134km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 131°   dip: 16°   rake: -123° Nodal Plane 2: strike: 345°   dip: 77°   rake: -81° Quality: azimuthalGap: -1°   stationPolarityCount: 132   misfitWeightCount: 23.4   misfit: 0.14   stationDistributionRatio: 0.53   meanDistP: 21.9   meanDistT: 29.7   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
First-motion Focal Mechanism (HASH):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 195°   dip: 25°   rake: -73° Nodal Plane 2: strike: 357°   dip: 66°   rake: -98° Quality: azimuthalGap: 40°   stationPolarityCount: 132   misfit: 0.26   stationDistributionRatio: 0.55   rmsAngDiffAccPref: 39.97   fracAcc30degPref: 0.43   qualityCode: D Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 216°   dip: 49°   rake: -126° Nodal Plane 2: strike: 84°   dip: 52°   rake: -56° Quality: azimuthalGap: -1°   stationPolarityCount: 19   misfitWeightCount: 5.6   misfit: 9999.90   stationDistributionRatio: 0.67   meanDistP: 27.2   meanDistT: 44.2   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_aref
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 121°   dip: 40°   rake: -62° Nodal Plane 2: strike: 266°   dip: 56°   rake: -111° Quality: azimuthalGap: -1°   stationPolarityCount: 9   misfitWeightCount: 4.1   misfit: 9999.90   stationDistributionRatio: 0.69   meanDistP: 28.7   meanDistT: 41.6   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

Event ID: smi:KOERI/ee/event/1791779892303
Event info last updated: 2026.10.12-05:38:48 UTC
Event first association/location: 2026.10.12-04:42:34 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI