Early-est:     Ascension Island Region    2026.06.20-06:43:20.70    q:C      mb:5.2*    Mwp:5.5    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1781937799684.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1781937799684.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1781937799684.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: 5.2* [82]    Mwp: 5.5 [18]    Mwpd: 5.7Xinv [16]
Region: Ascension Island Region
Origin Time: 2026.06.20-06:43:20.70 UTC
Hypocenter: lat: -6.84°  lon: -12.89°  [+/-50km]    depth: 15km  [+/-25km]
Location Quality: qualityCode:  C     stdErr: 1.7s   assocPhases: 122   usedPhases: 70
minDist: 1.8°   maxDist: 96.8°   AzGap: 75°   2ndAzGap: 99°   atten: -0.60 [+/-0.54]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 21km   maxHorUnc: 50km   azMaxHorUnc: 78°
68%ConfEllipsoid:   semiMajorAxisLength: 63km   majorAxisAzimuth: 257°   majorAxisPlunge: 7°   semiIntermediateAxisLength: 29km   intermediateAxisAzimuth: 161°   intermediateAxisPlunge: 39°   semiMinorAxisLength: 19km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [50]    Td: 3.1Xs [1]    Td*T50Ex: - [0]    To: 13.5s [49]
Closest plate boundaries:
   Africa - South America [oceanic transform fault]: distance: ~40km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 no
 no
 YES (40km)
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       5.5
       5.5
       5.5
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.1781937799684.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 83°   dip: 15°   rake: -163°
Nodal Plane 2: strike: 336°   dip: 86°   rake: -76°
Quality: azimuthalGap: -1°   stationPolarityCount: 63   misfitWeightCount: 7.5   misfit: 0.16   stationDistributionRatio: 0.71   meanDistP: 38.7   meanDistT: 38.5   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1781937799684.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (FMAMP_POLARITY_WAVEFORM):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 17°   dip: 37°   rake: 141°
Nodal Plane 2: strike: 140°   dip: 68°   rake: 60°
Quality: azimuthalGap: -1°   stationPolarityCount: 8   misfitWeightCount: 4.0   misfit: 0.06   stationDistributionRatio: 0.83   meanDistP: 53.3   meanDistT: 45.1   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity_waveform
./hypo.1781937799684.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 233°   dip: 10°   rake: -20°
Nodal Plane 2: strike: 343°   dip: 87°   rake: -99°
Quality: azimuthalGap: 75°   stationPolarityCount: 63   misfit: 0.18   stationDistributionRatio: 0.74   rmsAngDiffAccPref: 34.65   fracAcc30degPref: 0.56   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1781937799684.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1781937799684
Event info last updated: 2026.06.20-07:42:02 UTC
Event first association/location: 2026.06.20-06:53:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA