Early-est:     Volcano Islands, Japan Region    2026.10.04-11:12:49.72    q:A      mb:5.1    Mwp:-    Mwpd:-    Td*T50Ex:1.4     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: 5.1 [63]    Mwp: 5.5X [3]    Mwpd: 5.9Xinv [2] Region: Volcano Islands, Japan Region Origin Time: 2026.10.04-11:12:49.72 UTC Hypocenter: lat: 22.79°  lon: 144.78°  [+/-16km]    depth: 10km  [+/-14km] Location Quality: qualityCode:  A     stdErr: 1.5s   assocPhases: 109   usedPhases: 80 minDist: 4.9°   maxDist: 149.1°   AzGap: 42°   2ndAzGap: 51°   atten: -1.10 [+/-0.17] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 16km   azMaxHorUnc: 89° 68%ConfEllipsoid:   semiMajorAxisLength: 20km   majorAxisAzimuth: 89°   majorAxisPlunge: 8°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 349°   intermediateAxisPlunge: 50°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [59]    Td: 3.0s [5]    Td*T50Ex: 1.4 [5]    To: 28.5s [44] Closest plate boundaries:    Mariana / Pacific [subduction zone]: distance: ~50km    Philippine Sea - Mariana [oceanic spreading ridge]: distance: ~190km    Philippine Sea / Pacific [subduction zone]: distance: ~220km Subduction geometry:    Zone: Izu-Bonin    Slab depth at epicenter: 13km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (50km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    1.4    1.4    1.4 Td*To:      85.5      85.5      85.5 Mwp magnitude:        -        -        - Hypocenter depth:        10km        10km        10km Slab depth at epicenter:        13km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 171°   dip: 10°   rake: 32° Nodal Plane 2: strike: 50°   dip: 85°   rake: 99° Quality: azimuthalGap: -1°   stationPolarityCount: 64   misfitWeightCount: 11.8   misfit: 0.20   stationDistributionRatio: 0.31   meanDistP: 35.3   meanDistT: 26.7   qualityCode: C 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: 284°   dip: 72°   rake: -166° Nodal Plane 2: strike: 190°   dip: 77°   rake: -19° Quality: azimuthalGap: 42°   stationPolarityCount: 64   misfit: 0.37   stationDistributionRatio: 0.66   rmsAngDiffAccPref: 31.88   fracAcc30degPref: 0.69   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: 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/1791112369614
Event info last updated: 2026.10.04-12:13:11 UTC
Event first association/location: 2026.10.04-11:18:46 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI