Early-est:     Volcano Islands, Japan Region    2025.12.07-20:42:28.05    q:B      mb:4.4    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: 4.4 [26]    Mwp: - [0]    Mwpd: - [0] Region: Volcano Islands, Japan Region Origin Time: 2025.12.07-20:42:28.05 UTC Hypocenter: lat: 25.01°  lon: 141.50°  [+/-12km]    depth: 502km  [+/-18km] Location Quality: qualityCode:  B     stdErr: 1.0s   assocPhases: 64   usedPhases: 29 minDist: 2.2°   maxDist: 151.0°   AzGap: 92°   2ndAzGap: 153°   atten: -1.03 [+/-0.13] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 10km   maxHorUnc: 12km   azMaxHorUnc: 37° 68%ConfEllipsoid:   semiMajorAxisLength: 18km   majorAxisAzimuth: 39°   majorAxisPlunge: 71°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 216°   intermediateAxisPlunge: 19°   semiMinorAxisLength: 12km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.0 [13]    Td: -s [0]    Td*T50Ex: - [0]    To: 0.9s [9] Closest plate boundaries:    Philippine Sea / Pacific [subduction zone]: distance: ~160km Subduction geometry:    Zone: Izu-Bonin    Slab depth at epicenter: 107km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (160km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        502km        502km        502km Slab depth at epicenter:        107km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 275°   dip: 34°   rake: 80° Nodal Plane 2: strike: 107°   dip: 57°   rake: 97° Quality: azimuthalGap: -1°   stationPolarityCount: 27   misfitWeightCount: 8.2   misfit: 0.24   stationDistributionRatio: 0.54   meanDistP: 49.4   meanDistT: 48.6   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: 244°   dip: 22°   rake: 22° Nodal Plane 2: strike: 133°   dip: 82°   rake: 111° Quality: azimuthalGap: 71°   stationPolarityCount: 27   misfit: 0.33   stationDistributionRatio: 0.62   rmsAngDiffAccPref: 36.75   fracAcc30degPref: 0.64   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/1765140147199
Event info last updated: 2025.12.07-21:42:34 UTC
Event first association/location: 2025.12.07-20:50:49 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI