Early-est:     Off East Coast of Honshu, Japan    2025.11.09-22:41:32.13    q:A      mb:4.9    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: 4.9 [54]    Mwp: - [0]    Mwpd: - [0] Region: Off East Coast of Honshu, Japan Origin Time: 2025.11.09-22:41:32.13 UTC Hypocenter: lat: 39.54°  lon: 143.29°  [+/-16km]    depth: 10km  [+/-15km] Location Quality: qualityCode:  A     stdErr: 0.9s   assocPhases: 84   usedPhases: 66 minDist: 2.1°   maxDist: 158.3°   AzGap: 131°   2ndAzGap: 139°   atten: -1.07 [+/-0.15] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 14km   maxHorUnc: 16km   azMaxHorUnc: 126° 68%ConfEllipsoid:   semiMajorAxisLength: 19km   majorAxisAzimuth: 127°   majorAxisPlunge: 6°   semiIntermediateAxisLength: 17km   intermediateAxisAzimuth: 217°   intermediateAxisPlunge: 5°   semiMinorAxisLength: 14km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [34]    Td: 1.8Xs [2]    Td*T50Ex: - [0]    To: 17.1s [29] Closest plate boundaries:    Pacific \ Okhotsk [subduction zone]: distance: ~80km    Okhotsk / Pacific [subduction zone]: distance: ~180km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 17km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (80km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        10km        10km        10km Slab depth at epicenter:        17km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 84°   dip: 35°   rake: 72° Nodal Plane 2: strike: 286°   dip: 57°   rake: 102° Quality: azimuthalGap: -1°   stationPolarityCount: 57   misfitWeightCount: 6.9   misfit: 0.11   stationDistributionRatio: 0.62   meanDistP: 37.1   meanDistT: 27.5   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: 158°   dip: 89°   rake: 152° Nodal Plane 2: strike: 248°   dip: 62°   rake: 1° Quality: azimuthalGap: 131°   stationPolarityCount: 57   misfit: 0.32   stationDistributionRatio: 0.63   rmsAngDiffAccPref: 52.59   fracAcc30degPref: 0.35   qualityCode: D 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: 0° Nodal Plane 2: strike: 270°   dip: 90°   rake: 90° 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: 0° Nodal Plane 2: strike: 270°   dip: 90°   rake: 90° 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/1762728093010
Event info last updated: 2025.11.09-23:41:47 UTC
Event first association/location: 2025.11.09-22:51:51 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI