Early-est:     Hokkaido, Japan Region    2025.12.09-09:09:46.10    q:A      mb:5.3    Mwp:5.1    Mwpd:-    Td*T50Ex:0.6     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: 5.3 [135]    Mwp: 5.1 [5]    Mwpd: 5.8Xinv [4] Region: Hokkaido, Japan Region Origin Time: 2025.12.09-09:09:46.10 UTC Hypocenter: lat: 41.26°  lon: 142.46°  [+/-8km]    depth: 34km  [+/-11km] Location Quality: qualityCode:  A     stdErr: 1.4s   assocPhases: 197   usedPhases: 162 minDist: 0.9°   maxDist: 161.0°   AzGap: 53°   2ndAzGap: 72°   atten: -0.94 [+/-0.13] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 7km   maxHorUnc: 8km   azMaxHorUnc: 98° 68%ConfEllipsoid:   semiMajorAxisLength: 11km   majorAxisAzimuth: 120°   majorAxisPlunge: 80°   semiIntermediateAxisLength: 10km   intermediateAxisAzimuth: 276°   intermediateAxisPlunge: 9°   semiMinorAxisLength: 9km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [121]    Td: 1.3s [7]    Td*T50Ex: 0.6 [7]    To: 28.9s [107] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~170km    Okhotsk / Pacific [subduction zone]: distance: ~170km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 51km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (170km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    0.6    0.6    0.6 Td*To:      37.6      37.6      37.6 Mwp magnitude:        5.1        5.1        5.1 Hypocenter depth:        34km        34km        34km Slab depth at epicenter:        51km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY): Nodal Plane 1: strike: 120°   dip: 44°   rake: 4° Nodal Plane 2: strike: 27°   dip: 87°   rake: 134° Quality: azimuthalGap: -1°   stationPolarityCount: 141   misfitWeightCount: 23.4   misfit: 0.21   stationDistributionRatio: 0.40   meanDistP: 24.7   meanDistT: 17.6   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: 231°   dip: 81°   rake: -129° Nodal Plane 2: strike: 130°   dip: 40°   rake: -14° Quality: azimuthalGap: 52°   stationPolarityCount: 142   misfit: 0.35   stationDistributionRatio: 0.66   rmsAngDiffAccPref: 29.60   fracAcc30degPref: 0.77   qualityCode: C Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 325°   dip: 25°   rake: 122° Nodal Plane 2: strike: 111°   dip: 69°   rake: 76° Quality: azimuthalGap: -1°   stationPolarityCount: 20   misfitWeightCount: 3.6   misfit: 9999.90   stationDistributionRatio: 0.84   meanDistP: 47.1   meanDistT: 22.9   qualityCode: D 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/1765271386776
Event info last updated: 2025.12.09-10:09:57 UTC
Event first association/location: 2025.12.09-09:15:25 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI