Early-est:     Near East Coast of Honshu, Japan    2025.12.08-23:59:06.10    q:A      mb:5.3    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: 5.3 [106]    Mwp: 5.4X [2]    Mwpd: - [0] Region: Near East Coast of Honshu, Japan Origin Time: 2025.12.08-23:59:06.10 UTC Hypocenter: lat: 40.84°  lon: 142.90°  [+/-15km]    depth: 18km  [+/-14km] Location Quality: qualityCode:  A     stdErr: 1.3s   assocPhases: 188   usedPhases: 130 minDist: 1.2°   maxDist: 158.3°   AzGap: 47°   2ndAzGap: 60°   atten: -0.96 [+/-0.13] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 15km   azMaxHorUnc: 105° 68%ConfEllipsoid:   semiMajorAxisLength: 18km   majorAxisAzimuth: 105°   majorAxisPlunge: 1°   semiIntermediateAxisLength: 16km   intermediateAxisAzimuth: 15°   intermediateAxisPlunge: 7°   semiMinorAxisLength: 14km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [101]    Td: 1.7Xs [3]    Td*T50Ex: - [0]    To: 26.4s [91] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~130km    Okhotsk / Pacific [subduction zone]: distance: ~130km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 34km 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:        18km        18km        18km Slab depth at epicenter:        34km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 127°   dip: 60°   rake: -13° Nodal Plane 2: strike: 224°   dip: 79°   rake: -150° Quality: azimuthalGap: -1°   stationPolarityCount: 107   misfitWeightCount: 15.9   misfit: 0.13   stationDistributionRatio: 0.37   meanDistP: 28.3   meanDistT: 38.0   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: 211°   dip: 85°   rake: -103° Nodal Plane 2: strike: 99°   dip: 14°   rake: -23° Quality: azimuthalGap: 71°   stationPolarityCount: 107   misfit: 0.31   stationDistributionRatio: 0.61   rmsAngDiffAccPref: 31.50   fracAcc30degPref: 0.57   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/1765238347969
Event info last updated: 2025.12.09-00:59:23 UTC
Event first association/location: 2025.12.09-00:06:12 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI