Early-est:     Tonga Islands Region    2025.12.16-13:22:09.17    q:B      mb:4.6    Mwp:-    Mwpd:-    Td*T50Ex:-     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: 4.6 [14]    Mwp: - [0]    Mwpd: - [0] Region: Tonga Islands Region Origin Time: 2025.12.16-13:22:09.17 UTC Hypocenter: lat: -22.42°  lon: -175.68°  [+/-13km]    depth: 118km  [+/-16km] Location Quality: qualityCode:  B     stdErr: 1.3s   assocPhases: 56   usedPhases: 20 minDist: 6.3°   maxDist: 157.1°   AzGap: 136°   2ndAzGap: 171°   atten: -1.44 [+/-0.27] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 13km   azMaxHorUnc: 124° 68%ConfEllipsoid:   semiMajorAxisLength: 16km   majorAxisAzimuth: 110°   majorAxisPlunge: 52°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 323°   intermediateAxisPlunge: 33°   semiMinorAxisLength: 15km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.2 [10]    Td: 3.5Xs [1]    Td*T50Ex: - [0]    To: 1.2s [7] Closest plate boundaries:    Tonga - Australia [oceanic spreading ridge]: distance: ~100km    Tonga / Pacific [subduction zone]: distance: ~130km    Kermadec - Tonga [continental transform fault]: distance: ~160km    Kermadec / Pacific [subduction zone]: distance: ~160km Subduction geometry:    Zone: Kermadec-Tonga    Slab depth at epicenter: 54km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (130km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        118km        118km        118km Slab depth at epicenter:        54km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 27°   dip: 37°   rake: 107° Nodal Plane 2: strike: 185°   dip: 55°   rake: 77° Quality: azimuthalGap: -1°   stationPolarityCount: 19   misfitWeightCount: 5.9   misfit: 0.05   stationDistributionRatio: 0.54   meanDistP: 33.4   meanDistT: 34.3   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: 346°   dip: 32°   rake: 51° Nodal Plane 2: strike: 209°   dip: 66°   rake: 111° Quality: azimuthalGap: 108°   stationPolarityCount: 19   misfit: 0.53   stationDistributionRatio: 0.53   rmsAngDiffAccPref: 38.87   fracAcc30degPref: 0.59   qualityCode: D Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
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
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

Event ID: smi:KOERI/ee/event/1765891328892
Event info last updated: 2025.12.16-14:23:03 UTC
Event first association/location: 2025.12.16-13:29:28 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI