Early-est:     Off East Coast of Honshu, Japan    2025.12.13-21:49:38.49    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 [22]    Mwp: - [0]    Mwpd: - [0] Region: Off East Coast of Honshu, Japan Origin Time: 2025.12.13-21:49:38.49 UTC Hypocenter: lat: 40.66°  lon: 143.47°  [+/-19km]    depth: 10km  [+/-17km] Location Quality: qualityCode:  B     stdErr: 1.2s   assocPhases: 51   usedPhases: 25 minDist: 1.4°   maxDist: 144.8°   AzGap: 165°   2ndAzGap: 170°   atten: -0.61 [+/-0.19] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 15km   maxHorUnc: 19km   azMaxHorUnc: 105° 68%ConfEllipsoid:   semiMajorAxisLength: 24km   majorAxisAzimuth: 283°   majorAxisPlunge: 9°   semiIntermediateAxisLength: 19km   intermediateAxisAzimuth: 189°   intermediateAxisPlunge: 26°   semiMinorAxisLength: 16km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [18]    Td: 3.4Xs [1]    Td*T50Ex: - [0]    To: 20.3s [11] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~90km    Okhotsk / Pacific [subduction zone]: distance: ~90km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 19km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (90km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        10km        10km        10km Slab depth at epicenter:        19km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 128°   dip: 11°   rake: -23° Nodal Plane 2: strike: 241°   dip: 86°   rake: -100° Quality: azimuthalGap: -1°   stationPolarityCount: 20   misfitWeightCount: 5.0   misfit: 0.14   stationDistributionRatio: 0.45   meanDistP: 40.0   meanDistT: 31.7   qualityCode: D 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: 165°   stationPolarityCount: 20   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/1765662578460
Event info last updated: 2025.12.13-22:49:44 UTC
Event first association/location: 2025.12.13-22:26:02 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI