Early-est:     Hokkaido, Japan Region    2026.10.13-00:36:00.12    q:B      mb:4.3    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1791851760000.mech.fmamp_polarity.thumb.jpg     hash:./hypo.1791851760000.mech.hash.thumb.jpg     fmamp_amp_aref:./hypo.1791851760000.mech.fmamp_amp_aref.thumb.jpg     fmamp_amp_mwp:./hypo.1791851760000.mech.fmamp_amp_mwp.thumb.jpg

Automatic solution - this event has not been reviewed by a seismologist
Automatically determined event information may be incorrect!

Earthquake Details:
Magnitude: mb: 4.3 [7]    Mwp: - [0]    Mwpd: - [0]
Region: Hokkaido, Japan Region
Origin Time: 2026.10.13-00:36:00.12 UTC
Hypocenter: lat: 45.37°  lon: 143.39°  [+/-14km]    depth: 265km  [+/-15km]
Location Quality: qualityCode:  B     stdErr: 1.1s   assocPhases: 30   usedPhases: 14
minDist: 1.6°   maxDist: 72.4°   AzGap: 135°   2ndAzGap: 155°   atten: -1.12 [+/-0.36]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 14km   azMaxHorUnc: 77°
68%ConfEllipsoid:   semiMajorAxisLength: 17km   majorAxisAzimuth: 77°   majorAxisPlunge: 10°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 331°   intermediateAxisPlunge: 57°   semiMinorAxisLength: 15km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.0X [3]    Td: -s [0]    Td*T50Ex: - [0]    To: 0.9Xs [2]
Closest plate boundaries:
Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 242km
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 no
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       265km
       265km
       265km
Slab depth at epicenter:
       242km
       -
       -
./hypo.1791851760000.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 111°   dip: 41°   rake: -127°
Nodal Plane 2: strike: 336°   dip: 59°   rake: -62°
Quality: azimuthalGap: -1°   stationPolarityCount: 10   misfitWeightCount: 3.6   misfit: 0.14   stationDistributionRatio: 0.41   meanDistP: 43.4   meanDistT: 47.2   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1791851760000.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (HASH):    (No solution available)
Nodal Plane 1: strike: 999°   dip: 99°   rake: 999°
Nodal Plane 2: strike: 324°   dip: 13°   rake: 135°
Quality: azimuthalGap: 157°   stationPolarityCount: 10   misfit: 0.99   stationDistributionRatio: 0.00   rmsAngDiffAccPref: 0.00   fracAcc30degPref: 0.00   qualityCode: E
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1791851760000.mech.hash.mechanism.jpg
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
./hypo.1791851760000.mech.fmamp_amp_aref.mechanism.jpg
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
./hypo.1791851760000.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1791851760000
Event info last updated: 2026.10.13-01:36:02 UTC
Event first association/location: 2026.10.13-00:45:41 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI