Early-est:     Hokkaido, Japan Region    2025.12.11-18:11:07.73    q:B      mb:4.9    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: 4.9 [46]    Mwp: 4.5X [1]    Mwpd: - [0] Region: Hokkaido, Japan Region Origin Time: 2025.12.11-18:11:07.73 UTC Hypocenter: lat: 41.29°  lon: 142.76°  [+/-17km]    depth: 34km  [+/-17km] Location Quality: qualityCode:  B     stdErr: 1.3s   assocPhases: 93   usedPhases: 58 minDist: 0.8°   maxDist: 145.2°   AzGap: 141°   2ndAzGap: 149°   atten: -0.83 [+/-0.17] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 17km   azMaxHorUnc: 112° 68%ConfEllipsoid:   semiMajorAxisLength: 22km   majorAxisAzimuth: 289°   majorAxisPlunge: 15°   semiIntermediateAxisLength: 18km   intermediateAxisAzimuth: 182°   intermediateAxisPlunge: 48°   semiMinorAxisLength: 15km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [35]    Td: -s [0]    Td*T50Ex: - [0]    To: 2.9s [27] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~150km    Okhotsk / Pacific [subduction zone]: distance: ~150km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 42km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (150km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        34km        34km        34km Slab depth at epicenter:        42km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 59°   dip: 38°   rake: -104° Nodal Plane 2: strike: 256°   dip: 53°   rake: -80° Quality: azimuthalGap: -1°   stationPolarityCount: 51   misfitWeightCount: 10.6   misfit: 0.13   stationDistributionRatio: 0.51   meanDistP: 30.9   meanDistT: 31.8   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 53°   dip: 39°   rake: -105° Nodal Plane 2: strike: 252°   dip: 53°   rake: -78° Quality: azimuthalGap: 128°   stationPolarityCount: 51   misfit: 0.25   stationDistributionRatio: 0.66   rmsAngDiffAccPref: 28.05   fracAcc30degPref: 0.77   qualityCode: C 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/1765476667999
Event info last updated: 2025.12.11-19:11:20 UTC
Event first association/location: 2025.12.11-18:17:27 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI