Magnitude 8.8 – OFFSHORE MAULE, CHILE | Murmurs from the Earth...

A Great Earthquake of Magnitude 8.8 occurred off the coast of Chile this morning at 06:34:14 UTC. The extracted signal from my seismograph in northeastern Ohio shows severe clipping on the surface wave portion of the signal due to the size of this earthquake. This earthquake was approximately 500 times stronger (energy released) than the earthquake in Haiti last month.

The earthquake occurred offshore along the convergence zone of the Nazca and South American plates. This is a thrust fault due to the subduction of the Nazca plate under the South American plate. The earthquake occurred just 250 km north of the location of the largest earthquake recorded on instruments, a magnitude 9.5 event in May of 1960. A series of significant aftershocks is expected. One of these, at magnitude 6.9, occurred at 08:01:24 UTC.

The type of fault and its location and magnitude prompted several tsunami warnings and watches. The following tsunami levels have been reported:

 Location                   Lat.   Lon.    Time        Amplitude
 ------------------------  -----  ------  -------     -----------

 40min     SAN FELX    C  26.3S   80.1W  0809UTC       0.69M/2.3FT
 27min     Corral  Chile   39.9S   73.4W  0727UTC      1.45M/4.8FT
 40min     Talcahuano  C   36.7S   73.1W  0659UTC      1.80M/6.0FT
           VALPARAISO  C   33.0S   71.6W  0708UTC      2.60M/8.6FT

Time - Time of measurement.
Amp. - Tsunami amplitudes are measured relative to normal sea  level.  It is NOT crest-to-trough wave
height.  Values are given in both meters (M) and feet (FT).

The phase arrival time information for my location is shown below:

 delta   azimuth (degrees clockwise from north)
 (deg)      eq-to-station     station-to-eq
 76.50          352.8             172.4

                 travel   arrival time
    #  code      time(s)  dy hr mn sec
    1  P          706.39   0  6 46  0
    2  pP         717.33   0  6 46 11
    3  PcP        717.67   0  6 46 11
    4  sP         721.65   0  6 46 15
    5  PP         878.25   0  6 48 52
    6  PKiKP     1050.19   0  6 51 44
    7  pPKiKP    1061.66   0  6 51 55
    8  sPKiKP    1065.86   0  6 51 59
    9  SKiKP     1261.00   0  6 55 14
   10  S         1290.15   0  6 55 44
   11  pS        1304.08   0  6 55 58
   12  sS        1308.82   0  6 56  2
   13  SKSac     1314.20   0  6 56  8
   14  SKKSac    1315.27   0  6 56  9
   15  ScS       1319.14   0  6 56 13
   16  SPn       1326.49   0  6 56 20
   17  pSKSac    1329.16   0  6 56 23
   18  PnS       1331.50   0  6 56 25
   19  sSKSac    1333.57   0  6 56 27
   20  SS        1586.24   0  7  0 40
   21  PKKPdf    1846.31   0  7  5  0
   22  PKKPbc    1858.17   0  7  5 12
   23  SKKPdf    2057.33   0  7  8 31
   24  PKKSdf    2061.53   0  7  8 35
   25  SKKSdf    2272.32   0  7 12  6
   26  P'P'df    2341.82   0  7 13 15
   27  S'S'df    3201.00   0  7 27 35
   28  S'S'ac    3212.35   0  7 27 46
   29  LQ        1941.66   0  7  6 35
   30  LR        2154.97   0  7 10  8