## Introduction

The purpose of this display is to show the effect of a rejection filter on the processing. I consider events for which moment tensors have been obtained. I compare the ground velocities bandpass fitlered in the 0.02 - 0.10 Hz band on the left to those filtered with a rejection filter. Thue purpose of the filtering is to provide a simple waveform for inversion. At times the regional signal is affected by microseisms with frequency of about 0.16 Hz or by teleseismic surface waves with frequency of about 0.05 Hz.  Coherent noise is typically a problem with small events.  The reason that we want a simple waveform for the inversion is avoid the time shift operation of the inversion code latching onto the wrong peak.

We consider the following earthquakes:
• Earthquake of 20070806055945 Example of microseism rejection that also overcomes inadequacies of velocity model
• Earthquake of 20070818131630 Example of teleseism surface wave rejection
• Earthquake of 20090501013358 Example of microseism rejection that isolates pulse-like signal
In this comparison I use a standard time window of 10 seconds before predicted/observed P and 150 seconds after. In the actual inversion this window was mad much shorter to degradation of the goodness of fit parameter because of the post-signal noise.

## Earthquake of 20070806055945

The processing of the Nevada event is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20070806055945/index.html

` SLU Moment Tensor Solution 2007/08/06 05:59:45 37.811 -114.433 5.0 4.1 Nevada  Best Fitting Double Couple    Mo = 8.04e+21 dyne-cm    Mw = 3.87     Z  = 8 km     Plane   Strike  Dip  Rake      NP1       14    82   145      NP2      110    55    10 Principal Axes:   Axis    Value   Plunge  Azimuth     T   8.04e+21     30     326     N   0.00e+00     54     183     P  -8.04e+21     18      67 Moment Tensor: (dyne-cm)    Component  Value       Mxx     3.01e+21       Mxy    -5.39e+21       Mxz     2.00e+21       Myy    -4.32e+21       Myz    -4.10e+21       Mzz     1.31e+21                                                                                                                                                                                                                                         ############--                                   ################------                            ###################---------                        #####   ############----------                     ####### T ############------------                  ########   ###########--------------                #######################----------   --              -#######################---------- P ---             -######################-----------   ---            ---#####################------------------           -----##################-------------------           ------#################-------------------           --------##############--------------------            ----------###########-------------------             -------------#######--------------------              ----------------###-----------------##                -----------------######------#######                  ----------------##################                     -------------#################                        -----------#################                            -------###############                                   --############                                                                                                                                                                                  Harvard Convention Moment Tensor:      R          T          F  1.31e+21   2.00e+21   4.10e+21   2.00e+21   3.01e+21   5.39e+21   4.10e+21   5.39e+21  -4.32e+21 `

 Standard Filter Microseism Rejection Filter Filter: hp c 0.01 n 3 lp c 0.10 n 3 Filter: hp c 0.01 n 3 lp c 0.10 n 3 br c 0.12 0.25 n 4 p 2

## Earthquake of 20070818131630

The processing of this earthquake is documented at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20070818131630/index.html
` SLU Moment Tensor Solution 2007/08/18 13:16:30 38.07 -113.31 7.0 3.9 Utah  Best Fitting Double Couple    Mo = 3.76e+21 dyne-cm    Mw = 3.65     Z  = 9 km     Plane   Strike  Dip  Rake      NP1       65    75   -75      NP2      199    21   -134 Principal Axes:   Axis    Value   Plunge  Azimuth     T   3.76e+21     28     143     N   0.00e+00     14     241     P  -3.76e+21     57     355 Moment Tensor: (dyne-cm)    Component  Value       Mxx     7.71e+20       Mxy    -1.30e+21       Mxz    -2.96e+21       Myy     1.04e+21       Myz     1.10e+21       Mzz    -1.82e+21                                                                                                                                                                                                                                         #######-------                                   ######----------------                            ######----------------------                        #####-------------------------                     #####-----------------------------                  #####-----------   -----------------                #####------------ P -----------------#              #####-------------   ----------------###             ####-------------------------------#####            #####----------------------------#########           ####---------------------------###########           ####------------------------##############           ####--------------------##################            ###----------------#####################             ####----------##########################              ###---################################                ---#######################   #######                  ---###################### T ######                     --#####################   ####                        --##########################                            -#####################                                   ##############                                                                                                                                                                                  Harvard Convention Moment Tensor:      R          T          F -1.82e+21  -2.96e+21  -1.10e+21  -2.96e+21   7.71e+20   1.30e+21  -1.10e+21   1.30e+21   1.04e+21 `

 Standard Filter Teleseismic Surface Wave Rejection Filter: hp c 0.02 n 3 lp c 0.10 n 3 Filter: hp c 0.05 n 3 lp c 0.15 n 3 br c 0.045 0.055 n 4 p 2

## Earthquake of 20090501013358

The solution for this earthquake is to be found at the link http://eqinfo.eas.slu.edu/Earthquake_Center/MECH.NA/20090501013358/index.html
` USGS/SLU Moment Tensor Solution ENS  2009/05/01 01:33:58:0  36.85 -104.78   5.0 3.5 New Mexico  Stations used:   IU.ANMO TA.Q25A TA.R25A TA.S25A TA.T21A TA.T22A TA.T23A    TA.T24A TA.T25A TA.U21A TA.U24A TA.U25A TA.U26A TA.V24A    TA.V25A TA.W23A TA.W24A TA.X23A TA.X24A TA.X25A TA.X26A   Filtering commands used:   hp c 0.02 n 3   lp c 0.10 n 3   br c 0.12 0.25 n 4 p 2  Best Fitting Double Couple  Mo = 6.24e+20 dyne-cm  Mw = 3.13   Z  = 8 km  Plane   Strike  Dip  Rake   NP1      185    85    20   NP2       93    70   175  Principal Axes:   Axis    Value   Plunge  Azimuth    T   6.24e+20     18      51    N   0.00e+00     69     198    P  -6.24e+20     10     317 Moment Tensor: (dyne-cm)    Component   Value       Mxx    -1.02e+20       Mxy     5.78e+20       Mxz     3.26e+19       Myy     6.46e+19       Myz     2.14e+20       Mzz     3.70e+19                                                                                                                                                                                                                                         --------######                                   ------------##########                               ------------#############                        - P -----------###############                     ---   -----------############   ##                  ------------------############ T ###                -------------------############   ####              -------------------#####################             -------------------#####################            --------------------######################           #-------------------######################           ###-----------------######################           ########-----------####################---            ###############---############----------             ##################----------------------              #################---------------------                ################--------------------                  ###############-------------------                     #############-----------------                        ############----------------                            #########-------------                                   #####---------                                                                                                                                                                                  Global CMT Convention Moment Tensor:      R          T          P  3.70e+19   3.26e+19  -2.14e+20   3.26e+19  -1.02e+20  -5.78e+20  -2.14e+20  -5.78e+20   6.46e+19 `

 Standard Filter Microseism Reject filter Filter: hp c 0.02 n 3 lp c 0.10 n 3 Filter: hp c 0.02 n 3 lp c 0.10 n 3 br c 0.12 0.25 n 4 p 2