Early-est:     Off East Coast of Honshu, Japan    2025.12.08-15:57:56.74    q:B      mb:5.0    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: 5.0 [46]    Mwp: - [0]    Mwpd: - [0] Region: Off East Coast of Honshu, Japan Origin Time: 2025.12.08-15:57:56.74 UTC Hypocenter: lat: 40.91°  lon: 143.04°  [+/-21km]    depth: 18km  [+/-15km] Location Quality: qualityCode:  B     stdErr: 1.3s   assocPhases: 86   usedPhases: 59 minDist: 1.1°   maxDist: 151.8°   AzGap: 105°   2ndAzGap: 172°   atten: -0.99 [+/-0.18] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 14km   maxHorUnc: 21km   azMaxHorUnc: 109° 68%ConfEllipsoid:   semiMajorAxisLength: 26km   majorAxisAzimuth: 289°   majorAxisPlunge: 2°   semiIntermediateAxisLength: 18km   intermediateAxisAzimuth: 198°   intermediateAxisPlunge: 22°   semiMinorAxisLength: 15km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [39]    Td: -s [0]    Td*T50Ex: - [0]    To: 3.1s [30] 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: 31km 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:        18km        18km        18km Slab depth at epicenter:        31km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 142°   dip: 17°   rake: 136° Nodal Plane 2: strike: 274°   dip: 79°   rake: 78° Quality: azimuthalGap: -1°   stationPolarityCount: 50   misfitWeightCount: 7.9   misfit: 0.19   stationDistributionRatio: 0.44   meanDistP: 40.0   meanDistT: 51.5   qualityCode: D 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: 116°   dip: 11°   rake: 131° Nodal Plane 2: strike: 255°   dip: 82°   rake: 83° Quality: azimuthalGap: 104°   stationPolarityCount: 50   misfit: 0.31   stationDistributionRatio: 0.64   rmsAngDiffAccPref: 52.02   fracAcc30degPref: 0.31   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: 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/1765209475841
Event info last updated: 2025.12.08-16:58:03 UTC
Event first association/location: 2025.12.08-16:04:44 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI