Early-est:     Mariana Islands Region    2026.10.11-05:13:36.55    q:C      mb:4.2    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: 4.2 [10]    Mwp: - [0]    Mwpd: - [0] Region: Mariana Islands Region Origin Time: 2026.10.11-05:13:36.55 UTC Hypocenter: lat: 21.47°  lon: 143.09°  [+/-15km]    depth: 290km  [+/-16km] Location Quality: qualityCode:  C     stdErr: 0.8s   assocPhases: 44   usedPhases: 16 minDist: 5.6°   maxDist: 174.9°   AzGap: 85°   2ndAzGap: 105°   atten: -1.50 [+/-0.41] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 15km   azMaxHorUnc: 89° 68%ConfEllipsoid:   semiMajorAxisLength: 20km   majorAxisAzimuth: 271°   majorAxisPlunge: 23°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 58°   intermediateAxisPlunge: 63°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.4 [5]    Td: -s [0]    Td*T50Ex: - [0]    To: 0.7Xs [1] Closest plate boundaries:    Philippine Sea - Mariana [oceanic spreading ridge]: distance: ~20km    Mariana / Pacific [subduction zone]: distance: ~260km    Philippine Sea / Pacific [subduction zone]: distance: ~330km Subduction geometry:    Zone: Izu-Bonin    Slab depth at epicenter: 280km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (260km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        290km        290km        290km Slab depth at epicenter:        280km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 292°   dip: 4°   rake: -63° Nodal Plane 2: strike: 85°   dip: 87°   rake: -92° Quality: azimuthalGap: -1°   stationPolarityCount: 12   misfitWeightCount: 4.7   misfit: 0.08   stationDistributionRatio: 0.58   meanDistP: 31.5   meanDistT: 40.0   qualityCode: D 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: 257°   dip: 11°   rake: -111° Nodal Plane 2: strike: 99°   dip: 79°   rake: -86° Quality: azimuthalGap: 105°   stationPolarityCount: 12   misfit: 0.19   stationDistributionRatio: 0.72   rmsAngDiffAccPref: 43.11   fracAcc30degPref: 0.34   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: 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/1791695616550
Event info last updated: 2026.10.11-06:13:50 UTC
Event first association/location: 2026.10.11-06:10:48 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI