Early-est: Kodiak Island Region, Alaska 2026.10.06-18:34:31.25 q:A mb:5.3 Mwp:5.5 Mwpd:- Td*T50Ex:1.3 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: 5.3 [144] Mwp: 5.5 [10] Mwpd: 5.9Xinv [5]
Region:	Kodiak Island Region, Alaska
Origin Time:	2026.10.06-18:34:31.25 UTC
Hypocenter:	lat: 58.98° lon: -153.82° [+/-6km] depth: 61km [+/-7km]
Location Quality:	qualityCode: A stdErr: 1.2s assocPhases: 248 usedPhases: 184 minDist: 1.4° maxDist: 161.8° AzGap: 29° 2ndAzGap: 36° atten: -1.48 [+/-0.12]
Location Uncertainty:	68%ConfEllipse: minHorUnc: 5km maxHorUnc: 6km azMaxHorUnc: 172° 68%ConfEllipsoid: semiMajorAxisLength: 8km majorAxisAzimuth: 173° majorAxisPlunge: 32° semiIntermediateAxisLength: 7km intermediateAxisAzimuth: 264° intermediateAxisPlunge: 3° semiMinorAxisLength: 6km

Tsunamigeneic Assesment:

Discriminants:

Prob Underwater: <1%
T50Ex: 0.7 [122]    Td: 1.8s [12]    Td*T50Ex: 1.3 [12]    To: 44.1s [108]
Closest plate boundaries:
   North America / Pacific [subduction zone]: distance: ~330km
Subduction geometry:    Zone: Alaska-Aleutians    Slab depth at epicenter: 88km

Decision table (TEST!):

Event type:

Subduction Zone

Other Thrust/Normal

Strike-slip

Compatible close plate boundary?:

Prob underwater:

<1%

Td*T50Ex:

1.3

Td*To:

79.4

Mwp magnitude:

5.5

Hypocenter depth:

61km

Slab depth at epicenter:

88km

First-motion Focal Mechanism (FMAMP_POLARITY): (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1:	strike: 67° dip: 46° rake: 37°
Nodal Plane 2:	strike: 309° dip: 64° rake: 130°
Quality:	azimuthalGap: -1° stationPolarityCount: 150 misfitWeightCount: 31.6 misfit: 0.17 stationDistributionRatio: 0.55 meanDistP: 30.2 meanDistT: 19.8 qualityCode: C
Method:	methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity

./hypo.1791311672687.mech.fmamp_polarity.mechanism.jpg

First-motion Focal Mechanism (HASH): (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1:	strike: 350° dip: 58° rake: 112°
Nodal Plane 2:	strike: 133° dip: 38° rake: 59°
Quality:	azimuthalGap: 34° stationPolarityCount: 150 misfit: 0.20 stationDistributionRatio: 0.63 rmsAngDiffAccPref: 37.44 fracAcc30degPref: 0.51 qualityCode: D
Method:	methodID: smi:gov.usgs/focalmec/HASH_1.2

./hypo.1791311672687.mech.hash.mechanism.jpg

First-motion Focal Mechanism (FMAMP_AMP_AREF): (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1:	strike: 51° dip: 13° rake: -8°
Nodal Plane 2:	strike: 149° dip: 88° rake: -103°
Quality:	azimuthalGap: -1° stationPolarityCount: 25 misfitWeightCount: 4.9 misfit: 9999.90 stationDistributionRatio: 0.75 meanDistP: 23.4 meanDistT: 32.5 qualityCode: C
Method:	methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_aref

./hypo.1791311672687.mech.fmamp_amp_aref.mechanism.jpg

First-motion Focal Mechanism (FMAMP_AMP_MWP): (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1:	strike: 65° dip: 31° rake: 16°
Nodal Plane 2:	strike: 321° dip: 82° rake: 120°
Quality:	azimuthalGap: -1° stationPolarityCount: 8 misfitWeightCount: 5.3 misfit: 9999.90 stationDistributionRatio: 0.44 meanDistP: 29.8 meanDistT: 27.9 qualityCode: C
Method:	methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

./hypo.1791311672687.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1791311672687
Event info last updated: 2026.10.06-19:34:47 UTC
Event first association/location: 2026.10.06-18:38:11 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI

Early-est: Kodiak Island Region, Alaska 2026.10.06-18:34:31.25 q:A mb:5.3 Mwp:5.5 Mwpd:- Td*T50Ex:1.3 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!