Early-est:     South of Tonga Islands    2025.12.09-11:15:19.25    q:B      mb:4.7    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: 4.7 [17]    Mwp: - [0]    Mwpd: - [0] Region: South of Tonga Islands Origin Time: 2025.12.09-11:15:19.25 UTC Hypocenter: lat: -26.49°  lon: -175.55°  [+/-20km]    depth: 123km  [+/-33km] Location Quality: qualityCode:  B     stdErr: 1.8s   assocPhases: 34   usedPhases: 21 minDist: 9.0°   maxDist: 161.8°   AzGap: 92°   2ndAzGap: 111°   atten: -1.50 [+/-0.35] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 14km   maxHorUnc: 20km   azMaxHorUnc: 175° 68%ConfEllipsoid:   semiMajorAxisLength: 37km   majorAxisAzimuth: 357°   majorAxisPlunge: 57°   semiIntermediateAxisLength: 18km   intermediateAxisAzimuth: 135°   intermediateAxisPlunge: 25°   semiMinorAxisLength: 17km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [11]    Td: -s [0]    Td*T50Ex: - [0]    To: 8.0s [7] Closest plate boundaries:    Kermadec / Pacific [subduction zone]: distance: ~10km Subduction geometry:    Zone: Kermadec-Tonga    Slab depth at epicenter: 10km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (10km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        123km        123km        123km Slab depth at epicenter:        10km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 94°   dip: 33°   rake: -62° Nodal Plane 2: strike: 241°   dip: 61°   rake: -107° Quality: azimuthalGap: -1°   stationPolarityCount: 20   misfitWeightCount: 5.4   misfit: 0.09   stationDistributionRatio: 0.52   meanDistP: 31.6   meanDistT: 33.7   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: 65°   dip: 34°   rake: -101° Nodal Plane 2: strike: 259°   dip: 57°   rake: -82° Quality: azimuthalGap: 111°   stationPolarityCount: 20   misfit: 0.22   stationDistributionRatio: 0.51   rmsAngDiffAccPref: 37.29   fracAcc30degPref: 0.47   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: 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/1765278915502
Event info last updated: 2025.12.09-12:15:35 UTC
Event first association/location: 2025.12.09-11:22:25 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI