Early-est:     Chile - Argentina Border Region    2025.12.16-07:42:41.37    q:B      mb:4.2    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1765870961372.mech.fmamp_polarity.thumb.jpg     hash:./hypo.1765870961372.mech.hash.thumb.jpg     fmamp_amp_aref:./hypo.1765870961372.mech.fmamp_amp_aref.thumb.jpg     fmamp_amp_mwp:./hypo.1765870961372.mech.fmamp_amp_mwp.thumb.jpg

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

Earthquake Details:
Magnitude: mb: 4.2 [7]    Mwp: - [0]    Mwpd: - [0]
Region: Chile - Argentina Border Region
Origin Time: 2025.12.16-07:42:41.37 UTC
Hypocenter: lat: -33.03°  lon: -70.32°  [+/-15km]    depth: 126km  [+/-17km]
Location Quality: qualityCode:  B     stdErr: 0.9s   assocPhases: 15   usedPhases: 11
minDist: 0.3°   maxDist: 73.7°   AzGap: 85°   2ndAzGap: 122°   atten: -1.01 [+/-0.73]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 12km   maxHorUnc: 15km   azMaxHorUnc: 110°
68%ConfEllipsoid:   semiMajorAxisLength: 20km   majorAxisAzimuth: 295°   majorAxisPlunge: 33°   semiIntermediateAxisLength: 16km   intermediateAxisAzimuth: 68°   intermediateAxisPlunge: 46°   semiMinorAxisLength: 14km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: <1%
T50Ex: 0.2 [6]    Td: -s [0]    Td*T50Ex: - [0]    To: 1.0Xs [2]
Closest plate boundaries:
   Nazca \ South America [subduction zone]: distance: ~240km
Subduction geometry:    Zone: South America    Slab depth at epicenter: 85km
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (240km)
 no
 no
Prob underwater:
 <1%
 <1%
 <1%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       126km
       126km
       126km
Slab depth at epicenter:
       85km
       -
       -
./hypo.1765870961372.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 52°   dip: 35°   rake: 175°
Nodal Plane 2: strike: 146°   dip: 87°   rake: 55°
Quality: azimuthalGap: -1°   stationPolarityCount: 13   misfitWeightCount: 8.8   misfit: 0.16   stationDistributionRatio: 0.45   meanDistP: 32.6   meanDistT: 32.7   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1765870961372.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 38°   dip: 49°   rake: 161°
Nodal Plane 2: strike: 141°   dip: 76°   rake: 43°
Quality: azimuthalGap: 115°   stationPolarityCount: 13   misfit: 0.35   stationDistributionRatio: 0.65   rmsAngDiffAccPref: 41.31   fracAcc30degPref: 0.54   qualityCode: D
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1765870961372.mech.hash.mechanism.jpg
First-motion Focal Mechanism (FMAMP_AMP_AREF):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: nan°
Nodal Plane 2: strike: nan°   dip: nan°   rake: nan°
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/_amp_aref
./hypo.1765870961372.mech.fmamp_amp_aref.mechanism.jpg
First-motion Focal Mechanism (FMAMP_AMP_MWP):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: nan°
Nodal Plane 2: strike: nan°   dip: nan°   rake: nan°
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/_amp_mwp
./hypo.1765870961372.mech.fmamp_amp_mwp.mechanism.jpg

Event ID: smi:KOERI/ee/event/1765870961372
Event info last updated: 2025.12.16-08:42:46 UTC
Event first association/location: 2025.12.16-08:33:04 UTC
Software: Early-est 1.2.0 (2016.06.27)
Agency: KOERI