Early-est:     Hokkaido, Japan Region    2025.12.10-06:23:51.43    q:C      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 [14]    Mwp: - [0]    Mwpd: - [0] Region: Hokkaido, Japan Region Origin Time: 2025.12.10-06:23:51.43 UTC Hypocenter: lat: 41.32°  lon: 142.33°  [+/-14km]    depth: 20km  [+/-13km] Location Quality: qualityCode:  C     stdErr: 1.6s   assocPhases: 43   usedPhases: 19 minDist: 0.9°   maxDist: 157.9°   AzGap: 140°   2ndAzGap: 157°   atten: -0.74 [+/-0.21] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 10km   maxHorUnc: 14km   azMaxHorUnc: 97° 68%ConfEllipsoid:   semiMajorAxisLength: 18km   majorAxisAzimuth: 277°   majorAxisPlunge: 2°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 9°   intermediateAxisPlunge: 48°   semiMinorAxisLength: 12km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.6 [8]    Td: -s [0]    Td*T50Ex: - [0]    To: 8.5s [6] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~190km    Okhotsk / Pacific [subduction zone]: distance: ~190km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 55km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (190km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        20km        20km        20km Slab depth at epicenter:        55km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 72°   dip: 63°   rake: -158° Nodal Plane 2: strike: 331°   dip: 71°   rake: -29° Quality: azimuthalGap: -1°   stationPolarityCount: 16   misfitWeightCount: 4.4   misfit: 0.08   stationDistributionRatio: 0.50   meanDistP: 43.8   meanDistT: 44.3   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: 172°   stationPolarityCount: 16   misfit: 0.99   stationDistributionRatio: 0.62   rmsAngDiffAccPref: 21.01   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: 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/1765347831642
Event info last updated: 2025.12.10-07:24:04 UTC
Event first association/location: 2025.12.10-06:33:43 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI