Early-est:     South of Tonga Islands    2025.12.09-00:37:08.95    q:C      mb:4.8    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1765240631192.mech.fmamp_polarity.thumb.jpg     hash:./hypo.1765240631192.mech.hash.thumb.jpg     fmamp_amp_aref:./hypo.1765240631192.mech.fmamp_amp_aref.thumb.jpg     fmamp_amp_mwp:./hypo.1765240631192.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: 4.8 [13]    Mwp: - [0]    Mwpd: - [0]
Region: South of Tonga Islands
Origin Time: 2025.12.09-00:37:08.95 UTC
Hypocenter: lat: -26.95°  lon: -175.74°  [+/-47km]    depth: 20km  [+/-79km]
Location Quality: qualityCode:  C     stdErr: 1.3s   assocPhases: 38   usedPhases: 33
minDist: 9.5°   maxDist: 162.5°   AzGap: 99°   2ndAzGap: 135°   atten: -1.50 [+/-0.27]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 18km   maxHorUnc: 47km   azMaxHorUnc: 9°
68%ConfEllipsoid:   semiMajorAxisLength: 96km   majorAxisAzimuth: 11°   majorAxisPlunge: 55°   semiIntermediateAxisLength: 25km   intermediateAxisAzimuth: 140°   intermediateAxisPlunge: 24°   semiMinorAxisLength: 19km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [11]    Td: -s [0]    Td*T50Ex: - [0]    To: 12.6s [9]
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:
       20km
       20km
       20km
Slab depth at epicenter:
       13km
       -
       -
./hypo.1765240631192.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 78°   dip: 18°   rake: -157°
Nodal Plane 2: strike: 326°   dip: 83°   rake: -74°
Quality: azimuthalGap: -1°   stationPolarityCount: 28   misfitWeightCount: 3.0   misfit: 0.10   stationDistributionRatio: 0.63   meanDistP: 38.6   meanDistT: 32.2   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1765240631192.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 147°   dip: 22°   rake: -95°
Nodal Plane 2: strike: 332°   dip: 68°   rake: -88°
Quality: azimuthalGap: 134°   stationPolarityCount: 28   misfit: 0.26   stationDistributionRatio: 0.41   rmsAngDiffAccPref: 36.95   fracAcc30degPref: 0.47   qualityCode: D
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1765240631192.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.1765240631192.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.1765240631192.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1765240631192
Event info last updated: 2025.12.09-01:38:02 UTC
Event first association/location: 2025.12.09-00:59:06 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI