Early-est:     Near East Coast of Honshu, Japan    2025.12.08-14:15:08.35    q:B      mb:5.9    Mwp:7.4    Mwpd:7.5    Td*T50Ex:6.4     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: 5.9 [267]    Mwp: 7.4 [249]    Mwpd: 7.5 [248] Region: Near East Coast of Honshu, Japan Origin Time: 2025.12.08-14:15:08.35 UTC Hypocenter: lat: 40.82°  lon: 142.26°  [+/-14km]    depth: 20km  [+/-55km] Location Quality: qualityCode:  B     stdErr: 1.3s   assocPhases: 506   usedPhases: 357 minDist: 4.2°   maxDist: 162.3°   AzGap: 9°   2ndAzGap: 12°   atten: -1.04 [+/-0.17] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 14km   azMaxHorUnc: 46° 68%ConfEllipsoid:   semiMajorAxisLength: 56km   majorAxisAzimuth: 234°   majorAxisPlunge: 78°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 356°   intermediateAxisPlunge: 6°   semiMinorAxisLength: 14km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.8 [283]    Td: 7.9s [36]    Td*T50Ex: 6.4 [36]    To: 51.6s [270] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~180km    Okhotsk / Pacific [subduction zone]: distance: ~180km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 54km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (180km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    6.4    6.4    6.4 Td*To:      407.6      407.6      407.6 Mwp magnitude:        7.4        7.4        7.4 Hypocenter depth:        20km        20km        20km Slab depth at epicenter:        54km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY): Nodal Plane 1: strike: 167°   dip: 17°   rake: 51° Nodal Plane 2: strike: 27°   dip: 77°   rake: 101° Quality: azimuthalGap: -1°   stationPolarityCount: 348   misfitWeightCount: 53.9   misfit: 0.10   stationDistributionRatio: 0.57   meanDistP: 17.4   meanDistT: 15.0   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: 40°   dip: 55°   rake: 76° Nodal Plane 2: strike: 244°   dip: 38°   rake: 109° Quality: azimuthalGap: 11°   stationPolarityCount: 348   misfit: 0.08   stationDistributionRatio: 0.63   rmsAngDiffAccPref: 34.56   fracAcc30degPref: 0.60   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: 160°   dip: 24°   rake: 39° Nodal Plane 2: strike: 34°   dip: 75°   rake: 109° Quality: azimuthalGap: -1°   stationPolarityCount: 245   misfitWeightCount: 42.2   misfit: 9999.90   stationDistributionRatio: 0.65   meanDistP: 25.6   meanDistT: 27.8   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: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 144°   dip: 31°   rake: 24° Nodal Plane 2: strike: 33°   dip: 78°   rake: 119° Quality: azimuthalGap: -1°   stationPolarityCount: 237   misfitWeightCount: 36.0   misfit: 9999.90   stationDistributionRatio: 0.58   meanDistP: 25.9   meanDistT: 27.2   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

Event ID: smi:KOERI/ee/event/1765203311385
Event info last updated: 2025.12.08-15:16:54 UTC
Event first association/location: 2025.12.08-14:19:03 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI