Early-est: Off East Coast of Honshu, Japan 2025.11.10-09:59:02.50 q:B mb:5.1 Mwp:- Mwpd:- Td*T50Ex:0.9 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 [47] Mwp: 5.6X [2] Mwpd: 5.8Xinv [1]
Region:	Off East Coast of Honshu, Japan
Origin Time:	2025.11.10-09:59:02.50 UTC
Hypocenter:	lat: 39.68° lon: 143.12° [+/-21km] depth: 10km [+/-15km]
Location Quality:	qualityCode: B stdErr: 1.2s assocPhases: 99 usedPhases: 61 minDist: 1.9° maxDist: 86.0° AzGap: 121° 2ndAzGap: 134° atten: -0.86 [+/-0.17]
Location Uncertainty:	68%ConfEllipse: minHorUnc: 13km maxHorUnc: 21km azMaxHorUnc: 114° 68%ConfEllipsoid: semiMajorAxisLength: 26km majorAxisAzimuth: 294° majorAxisPlunge: 8° semiIntermediateAxisLength: 16km intermediateAxisAzimuth: 200° intermediateAxisPlunge: 23° semiMinorAxisLength: 14km

Tsunamigeneic Assesment:

Discriminants:

Prob Underwater: >99%
T50Ex: 0.5 [36]    Td: 1.9s [4]    Td*T50Ex: 0.9 [4]    To: 25.5s [28]
Closest plate boundaries:
   Pacific \ Okhotsk [subduction zone]: distance: ~100km
   Okhotsk / Pacific [subduction zone]: distance: ~170km
Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 21km

Decision table (TEST!):

Event type:

Subduction Zone

Other Thrust/Normal

Strike-slip

Compatible close plate boundary?:

YES (100km)

Prob underwater:

>99%

Td*T50Ex:

0.9

Td*To:

48.4

Mwp magnitude:

Hypocenter depth:

10km

Slab depth at epicenter:

21km

First-motion Focal Mechanism (FMAMP_POLARITY): (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1:	strike: 90° dip: 32° rake: 60°
Nodal Plane 2:	strike: 304° dip: 63° rake: 107°
Quality:	azimuthalGap: -1° stationPolarityCount: 52 misfitWeightCount: 10.8 misfit: 0.16 stationDistributionRatio: 0.49 meanDistP: 37.9 meanDistT: 30.3 qualityCode: C
Method:	methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity

./hypo.1762768742589.mech.fmamp_polarity.mechanism.jpg

First-motion Focal Mechanism (HASH): (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1:	strike: 73° dip: 19° rake: -14°
Nodal Plane 2:	strike: 176° dip: 85° rake: -108°
Quality:	azimuthalGap: 130° stationPolarityCount: 52 misfit: 0.25 stationDistributionRatio: 0.63 rmsAngDiffAccPref: 36.80 fracAcc30degPref: 0.57 qualityCode: D
Method:	methodID: smi:gov.usgs/focalmec/HASH_1.2

./hypo.1762768742589.mech.hash.mechanism.jpg

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

./hypo.1762768742589.mech.fmamp_amp_aref.mechanism.jpg

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

./hypo.1762768742589.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1762768742589
Event info last updated: 2025.11.10-10:59:43 UTC
Event first association/location: 2025.11.10-10:06:28 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI

Early-est: Off East Coast of Honshu, Japan 2025.11.10-09:59:02.50 q:B mb:5.1 Mwp:- Mwpd:- Td*T50Ex:0.9 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!

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