Early-est:     W. Caroline Islands, Micronesia    2026.08.17-22:53:13.73    q:B      mb:5.0*    Mwp:5.6    Mwpd:-    Td*T50Ex:1.9     fmamp_polarity:./hypo.1787007202341.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1787007202341.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1787007202341.mech.hash.thumb.jpg

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

Earthquake Details:
Magnitude: mb: 5.0* [29]    Mwp: 5.6 [9]    Mwpd: 5.7Xinv [7]
Region: W. Caroline Islands, Micronesia
Origin Time: 2026.08.17-22:53:13.73 UTC
Hypocenter: lat: 9.72°  lon: 138.51°  [+/-12km]    depth: 15km  [+/-20km]
Location Quality: qualityCode:  B     stdErr: 2.1s   assocPhases: 60   usedPhases: 32
minDist: 14.1°   maxDist: 157.6°   AzGap: 97°   2ndAzGap: 100°   atten: -0.34 [+/-0.44]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 11km   maxHorUnc: 12km   azMaxHorUnc: 82°
68%ConfEllipsoid:   semiMajorAxisLength: 20km   majorAxisAzimuth: 256°   majorAxisPlunge: 76°   semiIntermediateAxisLength: 15km   intermediateAxisAzimuth: 84°   intermediateAxisPlunge: 14°   semiMinorAxisLength: 13km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.7 [18]    Td: 2.9s [10]    Td*T50Ex: 1.9 [10]    To: 11.8s [14]
Closest plate boundaries:
   Philippine Sea / Pacific [subduction zone]: distance: ~30km
   Pacific - Caroline [oceanic transform fault]: distance: ~40km
   Philippine Sea - Caroline [oceanic convergent boundary]: distance: ~40km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (30km)
 YES (40km)
 YES (40km)
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   1.9
   1.9
   1.9
Td*To:
     34.2
     34.2
     34.2
Mwp magnitude:
       5.6
       5.6
       5.6
Hypocenter depth:
       15km
       15km
       15km
Slab depth at epicenter:
       n/a
       -
       -
Tsunami and Rupture predictions (TEST!): No prediction: Event too small (Mwp<7.0) or too few Mwp readings (N<20)
./hypo.1787007202341.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 147°   dip: 6°   rake: -14°
Nodal Plane 2: strike: 252°   dip: 88°   rake: -96°
Quality: azimuthalGap: -1°   stationPolarityCount: 26   misfitWeightCount: 6.9   misfit: 0.18   stationDistributionRatio: 0.31   meanDistP: 52.2   meanDistT: 45.2   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1787007202341.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (FMAMP_POLARITY_WAVEFORM):    (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/_polarity_waveform
./hypo.1787007202341.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 165°   dip: 11°   rake: -37°
Nodal Plane 2: strike: 292°   dip: 83°   rake: -99°
Quality: azimuthalGap: 107°   stationPolarityCount: 26   misfit: 0.27   stationDistributionRatio: 0.78   rmsAngDiffAccPref: 37.55   fracAcc30degPref: 0.54   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1787007202341.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1787007202341
Event info last updated: 2026.08.17-23:52:00 UTC
Event first association/location: 2026.08.17-23:01:00 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA