Early-est:     Near East Coast of Honshu, Japan    2025.12.16-02:45:36.20    q:B      mb:4.8    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: 4.8 [11]    Mwp: - [0]    Mwpd: - [0] Region: Near East Coast of Honshu, Japan Origin Time: 2025.12.16-02:45:36.20 UTC Hypocenter: lat: 38.71°  lon: 142.00°  [+/-15km]    depth: 90km  [+/-14km] Location Quality: qualityCode:  B     stdErr: 1.3s   assocPhases: 55   usedPhases: 16 minDist: 2.2°   maxDist: 151.3°   AzGap: 95°   2ndAzGap: 117°   atten: -1.60 [+/-0.31] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 15km   azMaxHorUnc: 115° 68%ConfEllipsoid:   semiMajorAxisLength: 19km   majorAxisAzimuth: 116°   majorAxisPlunge: 17°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 212°   intermediateAxisPlunge: 19°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [6]    Td: -s [0]    Td*T50Ex: - [0]    To: 5.2Xs [3] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~180km    Okhotsk / Pacific [subduction zone]: distance: ~320km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 43km 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:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        90km        90km        90km Slab depth at epicenter:        43km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 193°   dip: 63°   rake: -149° Nodal Plane 2: strike: 87°   dip: 63°   rake: -31° Quality: azimuthalGap: -1°   stationPolarityCount: 11   misfitWeightCount: 3.6   misfit: 0.09   stationDistributionRatio: 0.31   meanDistP: 40.2   meanDistT: 43.2   qualityCode: D 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: 199°   dip: 59°   rake: -161° Nodal Plane 2: strike: 99°   dip: 74°   rake: -32° Quality: azimuthalGap: 104°   stationPolarityCount: 11   misfit: 0.18   stationDistributionRatio: 0.64   rmsAngDiffAccPref: 35.73   fracAcc30degPref: 0.58   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/1765853136590
Event info last updated: 2025.12.16-03:45:43 UTC
Event first association/location: 2025.12.16-02:55:38 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI