Early-est:     Eastern Sea of Japan    2026.10.09-02:36:59.75    q:C      mb:4.5    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: 4.5 [5]    Mwp: - [0]    Mwpd: - [0] Region: Eastern Sea of Japan Origin Time: 2026.10.09-02:36:59.75 UTC Hypocenter: lat: 40.24°  lon: 137.76°  [+/-14km]    depth: 276km  [+/-19km] Location Quality: qualityCode:  C     stdErr: 1.1s   assocPhases: 12   usedPhases: 11 minDist: 2.6°   maxDist: 147.2°   AzGap: 108°   2ndAzGap: 119°   atten: -1.14 [+/-0.18] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 14km   azMaxHorUnc: 137° 68%ConfEllipsoid:   semiMajorAxisLength: 21km   majorAxisAzimuth: 139°   majorAxisPlunge: 61°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 313°   intermediateAxisPlunge: 29°   semiMinorAxisLength: 14km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.0X [1]    Td: -s [0]    Td*T50Ex: - [0]    To: 0.6Xs [1] Closest plate boundaries:    Okhotsk - Amur [oceanic convergent boundary]: distance: ~70km    Pacific \ Okhotsk [subduction zone]: distance: ~550km    Okhotsk / Pacific [subduction zone]: distance: ~570km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 231km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (550km)  YES (70km)  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        276km        276km        276km Slab depth at epicenter:        231km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 78°   dip: 12°   rake: 21° Nodal Plane 2: strike: 328°   dip: 86°   rake: 102° Quality: azimuthalGap: -1°   stationPolarityCount: 10   misfitWeightCount: 6.1   misfit: 0.08   stationDistributionRatio: 0.64   meanDistP: 29.0   meanDistT: 38.2   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
First-motion Focal Mechanism (HASH):    (No solution available) Nodal Plane 1: strike: 999°   dip: 99°   rake: 999° Nodal Plane 2: strike: 324°   dip: 13°   rake: 135° Quality: azimuthalGap: 194°   stationPolarityCount: 10   misfit: 0.99   stationDistributionRatio: 0.00   rmsAngDiffAccPref: 0.00   fracAcc30degPref: 0.00   qualityCode: E 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: 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
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

Event ID: smi:KOERI/ee/event/1791513419753
Event info last updated: 2026.10.09-03:37:02 UTC
Event first association/location: 2026.10.09-02:48:11 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI