Early-est:     Hokkaido, Japan Region    2025.12.08-22:07:19.65    q:B      mb:5.1    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: 5.1 [52]    Mwp: - [0]    Mwpd: - [0] Region: Hokkaido, Japan Region Origin Time: 2025.12.08-22:07:19.65 UTC Hypocenter: lat: 41.14°  lon: 142.90°  [+/-15km]    depth: 20km  [+/-13km] Location Quality: qualityCode:  B     stdErr: 1.8s   assocPhases: 96   usedPhases: 67 minDist: 0.9°   maxDist: 151.9°   AzGap: 72°   2ndAzGap: 136°   atten: -0.81 [+/-0.19] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 14km   maxHorUnc: 15km   azMaxHorUnc: 123° 68%ConfEllipsoid:   semiMajorAxisLength: 18km   majorAxisAzimuth: 123°   majorAxisPlunge: 2°   semiIntermediateAxisLength: 17km   intermediateAxisAzimuth: 213°   intermediateAxisPlunge: 5°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [41]    Td: 25.7Xs [1]    Td*T50Ex: - [0]    To: 2.4s [33] 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: 37km 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:        20km        20km        20km Slab depth at epicenter:        37km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY): Nodal Plane 1: strike: 51°   dip: 36°   rake: -68° Nodal Plane 2: strike: 205°   dip: 57°   rake: -105° Quality: azimuthalGap: -1°   stationPolarityCount: 61   misfitWeightCount: 11.0   misfit: 0.08   stationDistributionRatio: 0.59   meanDistP: 21.4   meanDistT: 24.6   qualityCode: B 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: 60°   dip: 25°   rake: -70° Nodal Plane 2: strike: 218°   dip: 66°   rake: -99° Quality: azimuthalGap: 108°   stationPolarityCount: 61   misfit: 0.21   stationDistributionRatio: 0.62   rmsAngDiffAccPref: 24.50   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: 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/1765231640071
Event info last updated: 2025.12.08-23:07:28 UTC
Event first association/location: 2025.12.08-22:16:06 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI