Subject: [IGSMAIL-5162]: Coseismic jump detected at Iquique due to the Mw 7.7 Tarapaca EQ
From: Michael Bevis <[email-masked]>
To: [email-masked], [email-masked], [email-masked]
Cc: Goran Ekstrom <[email-masked]>, Adam Dziewonski <[email-masked]>, "Richard O'Connell" <[email-masked]>
Date: Thu, 16 Jun 2005 14:18:23 -0400

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IGS Electronic Mail      16 Jun 13:02:33 PDT 2005      Message Number 5162
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Author: Michael Bevis

Dear Colleagues

The CGPS station IQQE in the coastal city of Iquique (N. Chile)
recorded a coseismic jump due to the 13 June Mw 7.7 mantle earthquake
beneath Tarapaca. This GPS station is located about 115 km WSW of the
epicenter, which is about one focal depth away.

Based on one day of data collected after the event, the coseismic
jump at IQQE has components

         west    42  mm
         up        40  mm
        south   12  mm

This result indicates that the fault plane is the more steeply
dipping (NP2) of the nodal planes identified in the Harvard CMT
announcement (copied below).

The GPS station lost some data due to electrical problems
precipitated by the event, and data communications remain fragile,
but the data is being deposited in the SOPAC archive as it becomes
available.

Eric Kendrick and Michael Bevis
Ohio State University

Hector Parra
Instituto Geografico Militar

***   REVISED HARVARD CMT   ***
June 13, 2005, TARAPACA, CHILE, MW=7.7 event

CENTROID, MOMENT TENSOR SOLUTION
HARVARD EVENT-FILE NAME M061305B
DATA USED: GSN
MANTLE WAVES:    73S,189C, T=150
CENTROID LOCATION:
ORIGIN TIME       22:44:40.5 0.1
LAT 20.02S 0.01;LON  69.17W 0.01
DEP  95.3 0.5;HALF-DURATION 18.2
MOMENT TENSOR; SCALE 10**27 D-CM
   MRR=-3.61 0.03; MTT=-0.26 0.02
   MPP= 3.86 0.02; MRT= 0.61 0.02
   MRP=-3.47 0.03; MTP=-0.25 0.01
  PRINCIPAL AXES:
  1.(T) VAL=  5.26;PLG=22;AZM= 85
  2.(N)      -0.25;     4;    353
  3.(P)      -5.02;    68;    254
BEST DOUBLE COUPLE:M0=5.1*10**27
  NP1:STRIKE=182;DIP=24;SLIP= -81
  NP2:STRIKE=352;DIP=67;SLIP= -94

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