Early-est:     Off East Coast of Honshu, Japan    2025.12.16-05:38:50.34    q:A      mb:5.3    Mwp:-    Mwpd:-    Td*T50Ex:0.8     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: 5.3 [109]    Mwp: 5.1X [3]    Mwpd: - [0] Region: Off East Coast of Honshu, Japan Origin Time: 2025.12.16-05:38:50.34 UTC Hypocenter: lat: 40.76°  lon: 143.19°  [+/-7km]    depth: 18km  [+/-8km] Location Quality: qualityCode:  A     stdErr: 1.4s   assocPhases: 183   usedPhases: 137 minDist: 1.6°   maxDist: 157.7°   AzGap: 44°   2ndAzGap: 58°   atten: -1.24 [+/-0.13] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 6km   maxHorUnc: 7km   azMaxHorUnc: 130° 68%ConfEllipsoid:   semiMajorAxisLength: 9km   majorAxisAzimuth: 187°   majorAxisPlunge: 52°   semiIntermediateAxisLength: 8km   intermediateAxisAzimuth: 292°   intermediateAxisPlunge: 11°   semiMinorAxisLength: 6km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [97]    Td: 1.7s [4]    Td*T50Ex: 0.8 [4]    To: 16.0s [81] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~110km    Okhotsk / Pacific [subduction zone]: distance: ~110km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 26km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (110km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    0.8    0.8    0.8 Td*To:      27.2      27.2      27.2 Mwp magnitude:        -        -        - Hypocenter depth:        18km        18km        18km Slab depth at epicenter:        26km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 129°   dip: 26°   rake: 34° Nodal Plane 2: strike: 8°   dip: 76°   rake: 112° Quality: azimuthalGap: -1°   stationPolarityCount: 123   misfitWeightCount: 13.6   misfit: 0.22   stationDistributionRatio: 0.49   meanDistP: 39.4   meanDistT: 27.0   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: 157°   dip: 9°   rake: 100° Nodal Plane 2: strike: 326°   dip: 81°   rake: 88° Quality: azimuthalGap: 46°   stationPolarityCount: 123   misfit: 0.41   stationDistributionRatio: 0.63   rmsAngDiffAccPref: 34.49   fracAcc30degPref: 0.55   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/1765863528973
Event info last updated: 2025.12.16-06:39:09 UTC
Event first association/location: 2025.12.16-05:45:04 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI