Early-est:     Off East Coast of Honshu, Japan    2025.12.12-03:21:38.71    q:A      mb:5.3    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: 5.3 [140]    Mwp: - [0]    Mwpd: 7.0Xinv [1] Region: Off East Coast of Honshu, Japan Origin Time: 2025.12.12-03:21:38.71 UTC Hypocenter: lat: 40.86°  lon: 143.07°  [+/-8km]    depth: 20km  [+/-9km] Location Quality: qualityCode:  A     stdErr: 1.2s   assocPhases: 210   usedPhases: 167 minDist: 1.2°   maxDist: 152.0°   AzGap: 83°   2ndAzGap: 93°   atten: -0.97 [+/-0.20] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 7km   maxHorUnc: 8km   azMaxHorUnc: 131° 68%ConfEllipsoid:   semiMajorAxisLength: 10km   majorAxisAzimuth: 310°   majorAxisPlunge: 20°   semiIntermediateAxisLength: 9km   intermediateAxisAzimuth: 164°   intermediateAxisPlunge: 66°   semiMinorAxisLength: 9km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [140]    Td: -s [0]    Td*T50Ex: - [0]    To: 30.1s [125] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~120km    Okhotsk / Pacific [subduction zone]: distance: ~120km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 30km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (120km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        20km        20km        20km Slab depth at epicenter:        30km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 284°   dip: 49°   rake: 124° Nodal Plane 2: strike: 59°   dip: 51°   rake: 57° Quality: azimuthalGap: -1°   stationPolarityCount: 158   misfitWeightCount: 19.6   misfit: 0.23   stationDistributionRatio: 0.54   meanDistP: 40.1   meanDistT: 20.8   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
First-motion Focal Mechanism (HASH):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 305°   dip: 41°   rake: 121° Nodal Plane 2: strike: 86°   dip: 56°   rake: 66° Quality: azimuthalGap: 79°   stationPolarityCount: 158   misfit: 0.35   stationDistributionRatio: 0.64   rmsAngDiffAccPref: 44.19   fracAcc30degPref: 0.34   qualityCode: D 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: 72°   dip: 75°   rake: -8° Nodal Plane 2: strike: 164°   dip: 82°   rake: -165° Quality: azimuthalGap: -1°   stationPolarityCount: 13   misfitWeightCount: 3.8   misfit: 9999.90   stationDistributionRatio: 0.23   meanDistP: 40.9   meanDistT: 32.2   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/1765509699057
Event info last updated: 2025.12.12-04:21:54 UTC
Event first association/location: 2025.12.12-03:28:06 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI