Early-est:     South of Tonga Islands    2025.12.09-20:31:26.24    q:B      mb:4.9    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: 4.9 [11]    Mwp: - [0]    Mwpd: - [0] Region: South of Tonga Islands Origin Time: 2025.12.09-20:31:26.24 UTC Hypocenter: lat: -26.60°  lon: -175.63°  [+/-13km]    depth: 96km  [+/-15km] Location Quality: qualityCode:  B     stdErr: 1.7s   assocPhases: 54   usedPhases: 19 minDist: 9.2°   maxDist: 158.3°   AzGap: 123°   2ndAzGap: 176°   atten: -1.70 [+/-0.36] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 13km   azMaxHorUnc: 135° 68%ConfEllipsoid:   semiMajorAxisLength: 17km   majorAxisAzimuth: 322°   majorAxisPlunge: 43°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 99°   intermediateAxisPlunge: 38°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [7]    Td: -s [0]    Td*T50Ex: - [0]    To: 12.2s [4] Closest plate boundaries:    Kermadec / Pacific [subduction zone]: distance: ~30km Subduction geometry:    Zone: Kermadec-Tonga    Slab depth at epicenter: 11km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (30km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        96km        96km        96km Slab depth at epicenter:        11km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 72°   dip: 54°   rake: 22° Nodal Plane 2: strike: 329°   dip: 72°   rake: 142° Quality: azimuthalGap: -1°   stationPolarityCount: 20   misfitWeightCount: 6.5   misfit: 0.06   stationDistributionRatio: 0.61   meanDistP: 39.2   meanDistT: 34.0   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 320°   dip: 75°   rake: 171° Nodal Plane 2: strike: 53°   dip: 81°   rake: 16° Quality: azimuthalGap: 126°   stationPolarityCount: 20   misfit: 0.36   stationDistributionRatio: 0.42   rmsAngDiffAccPref: 32.37   fracAcc30degPref: 0.78   qualityCode: C 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: 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/_amp_aref
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (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/_amp_mwp

Event ID: smi:KOERI/ee/event/1765312286288
Event info last updated: 2025.12.09-21:31:52 UTC
Event first association/location: 2025.12.09-20:39:21 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI