Early-est:     South Sandwich Islands Region    2026.09.29-06:38:47.01    q:B      mb:4.7*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1790663927092.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1790663927092.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1790663927092.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: 4.7* [8]    Mwp: - [0]    Mwpd: - [0]
Region: South Sandwich Islands Region
Origin Time: 2026.09.29-06:38:47.01 UTC
Hypocenter: lat: -55.30°  lon: -28.21°  [+/-16km]    depth: 9km  [+/-14km]
Location Quality: qualityCode:  B     stdErr: 1.0s   assocPhases: 14   usedPhases: 14
minDist: 4.9°   maxDist: 150.1°   AzGap: 96°   2ndAzGap: 118°   atten: -1.73 [+/-0.81]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 16km   azMaxHorUnc: 19°
68%ConfEllipsoid:   semiMajorAxisLength: 20km   majorAxisAzimuth: 20°   majorAxisPlunge: 8°   semiIntermediateAxisLength: 17km   intermediateAxisAzimuth: 111°   intermediateAxisPlunge: 8°   semiMinorAxisLength: 13km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.3 [4]    Td: -s [0]    Td*T50Ex: - [0]    To: 1.9s [4]
Closest plate boundaries:
   Sandwich / South America [oceanic transform fault]: distance: ~40km
   Scotia - South America [oceanic convergent boundary]: distance: ~90km
   Sandwich - Scotia [oceanic spreading ridge]: distance: ~90km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 no
 YES (90km)
 YES (40km)
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       9km
       9km
       9km
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.1790663927092.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 31°   dip: 27°   rake: -60°
Nodal Plane 2: strike: 178°   dip: 66°   rake: -104°
Quality: azimuthalGap: -1°   stationPolarityCount: 10   misfitWeightCount: 5.1   misfit: 0.00   stationDistributionRatio: 0.55   meanDistP: 39.0   meanDistT: 47.4   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1790663927092.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.1790663927092.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 350°   dip: 26°   rake: -104°
Nodal Plane 2: strike: 186°   dip: 65°   rake: -83°
Quality: azimuthalGap: 95°   stationPolarityCount: 10   misfit: 0.08   stationDistributionRatio: 0.57   rmsAngDiffAccPref: 35.89   fracAcc30degPref: 0.48   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1790663927092.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1790663927092
Event info last updated: 2026.09.29-07:37:01 UTC
Event first association/location: 2026.09.29-06:51:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA