Early-est:     Kuril Islands    2025.12.07-16:34:07.89    q:A      mb:5.4    Mwp:5.7    Mwpd:-    Td*T50Ex:1.0     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: 5.4 [206]    Mwp: 5.7 [12]    Mwpd: 5.8Xinv [8] Region: Kuril Islands Origin Time: 2025.12.07-16:34:07.89 UTC Hypocenter: lat: 50.10°  lon: 156.96°  [+/-15km]    depth: 20km  [+/-13km] Location Quality: qualityCode:  A     stdErr: 1.4s   assocPhases: 283   usedPhases: 240 minDist: 3.1°   maxDist: 158.1°   AzGap: 33°   2ndAzGap: 45°   atten: -0.92 [+/-0.19] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 15km   azMaxHorUnc: 134° 68%ConfEllipsoid:   semiMajorAxisLength: 19km   majorAxisAzimuth: 134°   majorAxisPlunge: 1°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 44°   intermediateAxisPlunge: 3°   semiMinorAxisLength: 13km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5 [188]    Td: 1.9s [10]    Td*T50Ex: 1.0 [10]    To: 27.9s [176] Closest plate boundaries:    Okhotsk / Pacific [subduction zone]: distance: ~100km    North America / Pacific [subduction zone]: distance: ~740km    Okhotsk / North America [subduction zone]: distance: ~740km Subduction geometry:    Zone: Kamchatka/Kurils/Japan    Slab depth at epicenter: 33km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (100km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    1.0    1.0    1.0 Td*To:      53.0      53.0      53.0 Mwp magnitude:        5.7        5.7        5.7 Hypocenter depth:        20km        20km        20km Slab depth at epicenter:        33km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY): Nodal Plane 1: strike: 73°   dip: 21°   rake: -69° Nodal Plane 2: strike: 231°   dip: 71°   rake: -98° Quality: azimuthalGap: -1°   stationPolarityCount: 211   misfitWeightCount: 25.7   misfit: 0.27   stationDistributionRatio: 0.62   meanDistP: 17.3   meanDistT: 16.4   qualityCode: B 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: 57°   dip: 41°   rake: -90° Nodal Plane 2: strike: 237°   dip: 49°   rake: -90° Quality: azimuthalGap: 32°   stationPolarityCount: 211   misfit: 0.37   stationDistributionRatio: 0.65   rmsAngDiffAccPref: 40.05   fracAcc30degPref: 0.37   qualityCode: D Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 135°   dip: 50°   rake: -51° Nodal Plane 2: strike: 263°   dip: 54°   rake: -127° Quality: azimuthalGap: -1°   stationPolarityCount: 24   misfitWeightCount: 6.2   misfit: 9999.90   stationDistributionRatio: 0.71   meanDistP: 22.3   meanDistT: 45.9   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_aref
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 134°   dip: 17°   rake: -12° Nodal Plane 2: strike: 236°   dip: 86°   rake: -107° Quality: azimuthalGap: -1°   stationPolarityCount: 9   misfitWeightCount: 3.0   misfit: 9999.90   stationDistributionRatio: 0.36   meanDistP: 36.0   meanDistT: 27.7   qualityCode: C Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

Event ID: smi:KOERI/ee/event/1765125246701
Event info last updated: 2025.12.07-17:35:00 UTC
Event first association/location: 2025.12.07-16:39:32 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI