Early-est:     Near East Coast of Honshu, Japan    2025.12.10-14:52:23.00    q:A      mb:5.5    Mwp:6.0    Mwpd:-    Td*T50Ex:1.2     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: 5.5 [205]    Mwp: 6.0 [77]    Mwpd: 6.2Xinv [67] Region: Near East Coast of Honshu, Japan Origin Time: 2025.12.10-14:52:23.00 UTC Hypocenter: lat: 40.75°  lon: 142.84°  [+/-10km]    depth: 20km  [+/-15km] Location Quality: qualityCode:  A     stdErr: 1.3s   assocPhases: 311   usedPhases: 261 minDist: 1.3°   maxDist: 160.8°   AzGap: 40°   2ndAzGap: 49°   atten: -0.71 [+/-0.16] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 7km   maxHorUnc: 10km   azMaxHorUnc: 112° 68%ConfEllipsoid:   semiMajorAxisLength: 16km   majorAxisAzimuth: 287°   majorAxisPlunge: 60°   semiIntermediateAxisLength: 11km   intermediateAxisAzimuth: 118°   intermediateAxisPlunge: 30°   semiMinorAxisLength: 9km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [213]    Td: 2.3s [24]    Td*T50Ex: 1.2 [24]    To: 29.4s [197] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~140km    Okhotsk / Pacific [subduction zone]: distance: ~140km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 35km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (140km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    1.2    1.2    1.2 Td*To:      67.6      67.6      67.6 Mwp magnitude:        6.0        6.0        6.0 Hypocenter depth:        20km        20km        20km Slab depth at epicenter:        35km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY): Nodal Plane 1: strike: 148°   dip: 13°   rake: 35° Nodal Plane 2: strike: 24°   dip: 83°   rake: 101° Quality: azimuthalGap: -1°   stationPolarityCount: 230   misfitWeightCount: 34.3   misfit: 0.15   stationDistributionRatio: 0.63   meanDistP: 16.7   meanDistT: 13.9   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: 224°   dip: 29°   rake: 105° Nodal Plane 2: strike: 27°   dip: 62°   rake: 82° Quality: azimuthalGap: 42°   stationPolarityCount: 231   misfit: 0.14   stationDistributionRatio: 0.64   rmsAngDiffAccPref: 36.42   fracAcc30degPref: 0.55   qualityCode: C Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 164°   dip: 26°   rake: 61° Nodal Plane 2: strike: 16°   dip: 68°   rake: 103° Quality: azimuthalGap: -1°   stationPolarityCount: 100   misfitWeightCount: 14.1   misfit: 9999.90   stationDistributionRatio: 0.88   meanDistP: 38.3   meanDistT: 22.4   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_aref
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 141°   dip: 21°   rake: 45° Nodal Plane 2: strike: 8°   dip: 75°   rake: 105° Quality: azimuthalGap: -1°   stationPolarityCount: 62   misfitWeightCount: 6.6   misfit: 9999.90   stationDistributionRatio: 0.87   meanDistP: 40.2   meanDistT: 30.2   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

Event ID: smi:KOERI/ee/event/1765378348183
Event info last updated: 2025.12.10-15:52:26 UTC
Event first association/location: 2025.12.10-14:54:44 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI