Mexico earthquake Mw 7.3 to 7.4 March 20, 2012 - Oaxaca - Guerrero

Earthquake having the characteritics of a subduction 
interplaque (thrust)event (all source inversions coincide
in this). The epicenter (USGS) is located
inland, near the border between the Oaxaca and Guerrero
states. Focal depth given between 10 and 27 km.

Some destructions are already reported in the old part of
far distance Mexico city (site effect expected).

No tsunami alert (no tsunami expected after NOAA)

21h57 french hour: after the president of Mexico, there
would not be heavy damages in the country.






Location NEIC - USGS:


Magnitude7.6
Date-Time
  • Tuesday, March 20, 2012 at 18:02:48 UTC
  • Tuesday, March 20, 2012 at 12:02:48 PM at epicenter
Location16.662°N, 98.188°W
Depth17.5 km (10.9 miles)
RegionOAXACA, MEXICO
Distances
  • 25 km (15 miles) E (95°) from Ometepec, Guerrero, Mexico
  • 42 km (26 miles) NNW (335°) from Pinotepa Nacional, Oaxaca, Mexico
  • 87 km (54 miles) SW (219°) from Tlaxiaco, Oaxaca, Mexico
  • 162 km (101 miles) WSW (255°) from Oaxaca, Oaxaca, Mexico
  • 186 km (115 miles) E (96°) from Acapulco, Guerrero, Mexico




Location EMSC (CSEM):

EARTHQUAKE on 20/03/2012 at 18:02 (UTC)
GUERRERO, MEXICO 10 km NW Huanjintepec

MAGNITUDE: Mw 7.3

Data provided by: BGSG GFZ IMP INGV LED MAD NEIC PDA PPTm PTWC
SC3 ZAMG

Latitude = 16.69 N
Longitude = 98.23 W
Origin Time = 18:02:49.6 (UTC)
Depth = 20 Km
RMS = 1.28 sec
Gap = 80 degrees
95% confidence ellipse: - Semi major = 5.5 Km
- Semi minor = 3.3 Km
- Azimuth of major axis = 28 degrees

Number of data used = 467

Preliminary location computed on Tue Mar 20 19:54:06 2012 (UTC)
Done by J-P Santoire




First source inversions:

USGS WPhase Moment Solution

12/03/20 18:02:48

Epicenter: 16.662 -98.187
MW 7.3

USGS/WPHASE CENTROID MOMENT TENSOR
12/03/20 18:02:48.00
Centroid: 16.262 -97.665
Depth 11 No. of sta: 30
Moment Tensor; Scale 10**19 Nm
Mrr= 6.30 Mtt=-6.17
Mpp=-0.13 Mrt= 8.97
Mrp=-6.92 Mtp= 1.74
Principal axes:
T Val= 13.26 Plg=58 Azm= 47
N = -0.45 9 301
P =-12.81 30 206

Best Double Couple:Mo=1.3*10**20
NP1:Strike=268 Dip=17 Slip= 55
NP2: 124 76 100
Moment Tensor Solution

Geoazur SCARDEC mechanism and source function



USGS Centroid Moment Solution

OAXACA, MEXICO

12/03/20 18:02:49.81

Epicenter: 16.665 -98.212
MW 7.3

USGS CENTROID MOMENT TENSOR
12/03/20 18:03:15.20
Centroid: 17.054 -98.118
Depth 10 No. of sta: 60
Moment Tensor; Scale 10**20 Nm
Mrr= 0.57 Mtt=-0.48
Mpp=-0.10 Mrt= 0.88
Mrp=-0.15 Mtp= 0.22
Principal axes:
T Val= 1.07 Plg=61 Azm= 2
N -0.02 7 104
P -1.05 29 198

Best Double Couple:Mo=1.1*10**20
NP1:Strike=102 Dip=74 Slip= 83
NP2: 306 17 113

Moment Tensor Solution



Shake map (USGS)







Ground deformation simulated by Jean-Claude Ruegg:

See attached files below

Message from JC Ruegg: message_JC_Ruegg_simulation_ground_deformation.txt

deformation file 1:cmt_8m6h_Ruegg.pdf

deformation file 2:120320_180249_8m6hA.SP_ruegg.pdf



GPS time series in the frame of ongoing project in mexico:


Posted by Nathalie Cotte and the ISTerre group






Č
Ċ
ď
cellule intervention postsismique,
20 mars 2012 23:25
Ċ
ď
cellule intervention postsismique,
20 mars 2012 23:24
ċ
ď
message_JC_Ruegg_simulation_ground_deformation.txt
(2k)
cellule intervention postsismique,
20 mars 2012 23:24
Comments