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KNZ issue with broadband vs. accelerometer comparison #87

Closed SquirrelKnight closed 11 months ago

SquirrelKnight commented 2 years ago

Possible time-dependent issue with station KNZ.

pSA_diff_KNZ_datetime

Events used for computations are as follows:

'2014p422047', '2014p751490', '2015p718332', '2020p239907', '2020p263458', '2020p598678'

elidana commented 2 years ago

thanks a lot for providing those details @SquirrelKnight !

Can you please confirm what is the event (within the group of 2020) that is giving the mismatch? Thanks!

salichon commented 2 years ago

First install okay: Kinemetrics Inc. | FBA-ES-T | 281 | KNZ | 20 | 0 | | 0 | 0 | 0 | 0 | 0 | 0 | 1999-12-15T22:30:01Z | 2019-07-09T22:40:00Z (with a Q330 datalogger)

2014p422047', '2014p751490', '2015p718332',

Second install: not okay: kinemetrics Inc. | FBA-ES-T | 990 | KNZ | 20 | 0 |   | 0 | 0 | 0 | 0 | 0 | 0 | 2019-07-09T23:15:00Z | 2021-06-02T21:56:00Z as in " is of most use for accelerometers). KNZ-20 is a standalone FBA-ES-T (EpisSensor) in the vault. Some digging in delta shows it was first deployed in the network at WAZ in 2003. Due to it's age and the problems we've have with the zinc whiskers producing stepping in FBA-ES-T's I would agree it's worth pulling out and replacing."

With a ln ratio of 0.7 that implies the PGA values are roughly 1/2 half (or twice) of their actual values (season 2019/2020)

2020p239907', '2020p263458', '2020p598678'

Last install From: 2021-06-03T04:19:00| The cabinet where the digitisers are currently located (~15m from Vault) will be upgraded and recorder (TitanSMA) will be installed in base of this cabinet. This will give the station an identical system design to the replacement station at KUZ.

2021p665417 ~M >4.5 ~100/200km distance from KNZ 

<station code="KNZ" name="KNZ" netid="NZ" insttype="CMG-3ES |   <station code="KNZ" name="KNZ" netid="NZ" insttype="Titan" 
    <comp name="10.HHE">                                      |     <comp name="21.HNE">
      <acc value="0.0317133865" flag="0"/>                    |       <acc value="0.0716887840" flag="0"/>
      <vel value="0.0142480323" flag="0"/>                    |       <vel value="0.0225092319" flag="0"/>
      <psa03 value="0.0675525027" flag="0"/>                  |       <psa03 value="0.1010203470" flag="0"/>
      <psa10 value="0.0163815421" flag="0"/>                  |       <psa10 value="0.0180286412" flag="0"/>
      <psa30 value="0.0019490105" flag="0"/>                  |       <psa30 value="0.0019329157" flag="0"/>
    </comp>                                                         </comp>
    <comp name="10.HHN">                                      |     <comp name="21.HNN">
      <acc value="0.0225541704" flag="0"/>                    |       <acc value="0.0520167376" flag="0"/>
      <vel value="0.0101862530" flag="0"/>                    |       <vel value="0.0171982652" flag="0"/>
      <psa03 value="0.0694528848" flag="0"/>                  |       <psa03 value="0.1025806959" flag="0"/>
      <psa10 value="0.0181652623" flag="0"/>                  |       <psa10 value="0.0179697375" flag="0"/>
      <psa30 value="0.0023351315" flag="0"/>                  |       <psa30 value="0.0015136400" flag="0"/>
    </comp>                                                         </comp>
    <comp name="10.HHZ">                                      |     <comp name="21.HNZ">
      <acc value="0.0298382129" flag="0"/>                    |       <acc value="0.0440552344" flag="0"/>
      <vel value="0.0118507271" flag="0"/>                    |       <vel value="0.0141371462" flag="0"/>
      <psa03 value="0.0787275531" flag="0"/>                  |       <psa03 value="0.0859528284" flag="0"/>
      <psa10 value="0.0140953218" flag="0"/>                  |       <psa10 value="0.0142443483" flag="0"/>
      <psa30 value="0.0011360024" flag="0"/>                  |       <psa30 value="0.0012939886" flag="0"/>

Values are consistent

salichon commented 2 years ago

PSA HH Vs HN are consistent from 2021Sep : 2021p665417 event image

KNZ HH Vs HH summary (strong likelihood for) Instrumentation 2019/2021 issue fixed in June 2021

FYI @SquirrelKnight @elidana

when happy we can close this one :)

NOTE: I might recommend to confirm the HH/HN consistency and check the orientation of KNZ HN 21 (using additional close recent events). The 2 instruments are NOT at the same location at all. (the above close is M4.9 only)

salichon commented 2 years ago

2020p239907', '2020p263458', '2020p598678' shown still roughly strong horizontals dampened Most simple explanation with regards to the previous like 4 like swap over time: Sensor aged

Unless more invest into that This can be Closed :)

salichon commented 2 years ago

The comparison of the SM is still not consistent and way too large wrt nearby strong motion and BB The KNZ SM values are way (x5) above the values given by the the broadband and times larger than the closest strong motion values WFSS. (https://strongmotion.geonet.org.nz/#/event/2019p738432) As in for the event 2019p738432 M5.7 <50 km below: 

<station code="KNZ" name="KNZ" netid="NZ" insttype="CMG-3ES |   <station code="KNZ" name="KNZ" netid="NZ" insttype="FBA-ES-
    <comp name="10.HHE">                                      |     <comp name="20.BNE">
      <acc value="2.9756635663" flag="0"/>                    |       <acc value="15.7742270760" flag="0"/>
      <vel value="0.9623211824" flag="0"/>                    |       <vel value="16.1925394070" flag="0"/>
      <psa03 value="2.5675850819" flag="0"/>                  |       <psa03 value="34.9436504119" flag="0"/>
      <psa10 value="1.5796799383" flag="0"/>                  |       <psa10 value="20.9181860215" flag="0"/>
      <psa30 value="0.0951970019" flag="0"/>                  |       <psa30 value="1.5875533053" flag="0"/>
    </comp>                                                         </comp>
    <comp name="10.HHN">                                      |     <comp name="20.BNN">
      <acc value="1.8192477235" flag="0"/>                    |       <acc value="14.2548082021" flag="0"/>
      <vel value="0.9139190071" flag="0"/>                    |       <vel value="12.9519810871" flag="0"/>
      <psa03 value="1.6582304162" flag="0"/>                  |       <psa03 value="23.7975818802" flag="0"/>
      <psa10 value="1.9282352190" flag="0"/>                  |       <psa10 value="17.7463832789" flag="0"/>
      <psa30 value="0.1765215813" flag="0"/>                  |       <psa30 value="1.0339015572" flag="0"/>
    </comp>                                                         </comp>
    <comp name="10.HHZ">                                      |     <comp name="20.BNZ">
      <acc value="2.1367517497" flag="0"/>                    |       <acc value="15.0488711768" flag="0"/>
      <vel value="0.8912020955" flag="0"/>                    |       <vel value="8.2267412029" flag="0"/>
      <psa03 value="2.6011763426" flag="0"/>                  |       <psa03 value="21.8790315914" flag="0"/>
      <psa10 value="1.6853174698" flag="0"/>                  |       <psa10 value="13.7952833621" flag="0"/>
      <psa30 value="0.0902348252" flag="0"/>                  |       <psa30 value="0.7616685292" flag="0"/>
    </comp>                                                         </comp>
  </station>                                                      </station>
  <station code="WFSS" name="WFSS" netid="NZ" insttype="FBA-E     <station code="WFSS" name="WFSS" netid="NZ" insttype="FBA-E
    <comp name="20.BN1">                                            <comp name="20.BN1">
      <acc value="3.9032335954" flag="0"/>                            <acc value="3.9032335954" flag="0"/>
      <vel value="3.4901457569" flag="0"/>                            <vel value="3.4901457569" flag="0"/>
      <psa03 value="11.0695004645" flag="0"/>                         <psa03 value="11.0695004645" flag="0"/>
      <psa10 value="5.5141414902" flag="0"/>                          <psa10 value="5.5141414902" flag="0"/>
      <psa30 value="0.2538025632" flag="0"/>                          <psa30 value="0.2538025632" flag="0"/>
    </comp>                                                         </comp>
    <comp name="20.BN2">                                            <comp name="20.BN2">
      <acc value="4.4252209363" flag="0"/>                            <acc value="4.4252209363" flag="0"/>
      <vel value="1.8928184182" flag="0"/>                            <vel value="1.8928184182" flag="0"/>
      <psa03 value="7.9006851337" flag="0"/>                          <psa03 value="7.9006851337" flag="0"/>
      <psa10 value="3.3314466066" flag="0"/>                          <psa10 value="3.3314466066" flag="0"/>
      <psa30 value="0.1424638572" flag="0"/>                          <psa30 value="0.1424638572" flag="0"/>
    </comp>                                                         </comp>
    <comp name="20.BNZ">                                            <comp name="20.BNZ">
      <acc value="1.2635347883" flag="0"/>                            <acc value="1.2635347883" flag="0"/>
      <vel value="0.7213764376" flag="0"/>                            <vel value="0.7213764376" flag="0"/>
      <psa03 value="3.7450146812" flag="0"/>                          <psa03 value="3.7450146812" flag="0"/>
      <psa10 value="0.8327103250" flag="0"/>                          <psa10 value="0.8327103250" flag="0"/>
      <psa30 value="0.0957088890" flag="0"/>                          <psa30 value="0.0957088890" flag="0"/>
    </comp>                                                         </comp>
  </station>                                                      </station>

As a conclusion i deem SM values most likely unreliable for the period 2019-07-09T23:15:00Z | 2021-06-02T21:56:00Z Before the sensor replacement.

FYI @mnaguit @SquirrelKnight

can be closed upon acceptance.

salichon commented 2 years ago

@mnaguit the KNZ ground is KNZ | Kokohu | Stable |   | On concrete floor of purpose-built instrument vault | Near base of steep rock spur | Hikurangi Subduction Zone, Raukumara F2 (c. 11 km) |   | A, Rock (Vs greater than 600m/s) or very thin soil (less than 5m) over rock | B, Rock | A, Rock or very stiff soil So to me there are no reason for rasonable site amplification at the time.

@mnaguit i would aim at getting final - peer - confirmation that the SM observations at this national site are questionable for the period 2019/07 to 2021/06.

Cheers :)