Early-est:     Mariana Islands    2025.12.15-23:06:03.88    q:B      mb:5.5    Mwp:5.7    Mwpd:-    Td*T50Ex:1.2     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: 5.5 [159]    Mwp: 5.7 [23]    Mwpd: 5.8Xinv [20] Region: Mariana Islands Origin Time: 2025.12.15-23:06:03.88 UTC Hypocenter: lat: 14.23°  lon: 146.07°  [+/-18km]    depth: 6km  [+/-49km] Location Quality: qualityCode:  B     stdErr: 1.4s   assocPhases: 274   usedPhases: 188 minDist: 8.8°   maxDist: 167.2°   AzGap: 23°   2ndAzGap: 26°   atten: -1.28 [+/-0.15] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 16km   maxHorUnc: 18km   azMaxHorUnc: 91° 68%ConfEllipsoid:   semiMajorAxisLength: 49km   majorAxisAzimuth: 258°   majorAxisPlunge: 83°   semiIntermediateAxisLength: 22km   intermediateAxisAzimuth: 95°   intermediateAxisPlunge: 6°   semiMinorAxisLength: 20km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.6 [118]    Td: 2.1s [27]    Td*T50Ex: 1.2 [27]    To: 3.5s [111] Closest plate boundaries:    Mariana / Pacific [subduction zone]: distance: ~120km    Philippine Sea - Mariana [oceanic transform fault]: distance: ~180km    Philippine Sea / Pacific [subduction zone]: distance: ~440km Subduction geometry:    Zone: Izu-Bonin    Slab depth at epicenter: 50km Decision table (TEST!): Event type: Subduction Zone Other Thrust/Normal Strike-slip Compatible close plate boundary?:  YES (120km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    1.2    1.2    1.2 Td*To:      7.4      7.4      7.4 Mwp magnitude:        5.7        5.7        5.7 Hypocenter depth:        6km        6km        6km Slab depth at epicenter:        50km        -        -

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 17°   dip: 54°   rake: 170° Nodal Plane 2: strike: 113°   dip: 82°   rake: 37° Quality: azimuthalGap: -1°   stationPolarityCount: 174   misfitWeightCount: 23.3   misfit: 0.21   stationDistributionRatio: 0.55   meanDistP: 35.7   meanDistT: 26.7   qualityCode: C 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: 319°   dip: 26°   rake: 154° Nodal Plane 2: strike: 73°   dip: 79°   rake: 66° Quality: azimuthalGap: 22°   stationPolarityCount: 174   misfit: 0.27   stationDistributionRatio: 0.62   rmsAngDiffAccPref: 30.16   fracAcc30degPref: 0.62   qualityCode: C Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
First-motion Focal Mechanism (FMAMP_AMP_AREF): Nodal Plane 1: strike: 106°   dip: 73°   rake: 13° Nodal Plane 2: strike: 13°   dip: 78°   rake: 163° Quality: azimuthalGap: -1°   stationPolarityCount: 49   misfitWeightCount: 6.8   misfit: 9999.90   stationDistributionRatio: 0.35   meanDistP: 20.6   meanDistT: 19.3   qualityCode: B Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_aref
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 88°   dip: 53°   rake: -12° Nodal Plane 2: strike: 186°   dip: 80°   rake: -142° Quality: azimuthalGap: -1°   stationPolarityCount: 21   misfitWeightCount: 4.8   misfit: 9999.90   stationDistributionRatio: 0.47   meanDistP: 40.7   meanDistT: 29.9   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_amp_mwp

Event ID: smi:KOERI/ee/event/1765839978253
Event info last updated: 2025.12.16-00:06:40 UTC
Event first association/location: 2025.12.15-23:14:03 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI