3 MARCH 1987 Modification History: ***01 June 1989: added comments regarding 1s and 10s filters on tellurics This is README file for distribution EMSLAB data tape from Alan G. Jones, now of DIAS, but formerly of the Geological Survey of Canada. Please address all communication to:- Prof. Alan G. Jones School of Cosmic Physics Dublin Institute for Advanced Studies 5 Merrion Square Dublin 2 Ireland tel: +353-1-662-1333 email: alan@cp.dias.ie The EMSLAB time series data may be used for research and analysis purposes provided that you agree to the following caveats: (1) On any publication resulting from any use of this data, I am invited to be a co-author. However, should you make any statements in the publication with which I do not agree, and should we be unable to come to some compromise, then I will only require that the data source be acknowledged. I am prepared to work with you in a co-operative manner if you so desire. (2) This data is given on a "caveat emptor" basis. There are still "glitches" in it,mainly "steps" as discussed for sites EMSL02, EMSL05 & EMSL11. I have tried to clean it up as much as I can. (3) You inform me that you have downloaded the data. (4) You inform me of any major corrections to the data that you make. This is so that I can keep an updated error file for distribution. File Contents length in records 1 this info 563 2 EMSL01 97966 3 EMSL02 87718 4 EMSL04 87718 5 EMSL05 97112 6 EMSL06 95465 7 EMSL08 96807 8 EMSL10 87840 9 EMSL11 87596 10 EMSL13 84851 11 EMSL14 84729 DATA ==== The 5 field components were sampled at 20 s, and the data are stored between hour markers, which are on the hour. The data are multiplexed, and are stored in the order Hx(H), Hy(D), Hz(Z), Ex(N), Ey(E), in units of 1/10 nT and 1/10 mV/km respectively. The data format is a "header" record, giving the 6-character station code followed by a 10-character hour time (yymmddhhmm), followed by 60 records giving the data for that hour in 15I5. The first data points AFTER the hour mark are for one digitizing interval later. Thus the data for the hour beginning 1 pm on 16th September, 1985, for station MF1.01 (EMSL01) looks like:- EMSL018509161300 26 615 53 93 195 21 615 53 97 195 24 617 56 93 187 24 620 56 102 184 24 625 58 102 176 26 634 63 115 161 etc. where the Hx field at 13:00:20 is 2.6 nT Hy 61.5 nT Hz 5.3 nT Ex 9.3 mV/km Ey 19.5 mV/km The missing data marker (caused either by cassette changing, no data, off-scale components, or data deleted by myself because of known errors) is -9999. The data are in GEOMAGNETIC co-ordinates, and an appropriate general declination value to use for all sites is -19.5, i.e., 19.5 degrees anti- clockwise, to rotate into geographical co-ordinates. INSTRUMENTS =========== Magnetometers: EDA Fluxgates, sensitivity of approx. 0.25 nT, Filters: HiPass -3dB points at 40 s no LoPass filters used, (NOTE: the objective of these data were to give the MT responses out to 30000 s, so not all sites were sufficiently well protected to permit estimation of the GDS transfer functions much beyond that due to thermal effects. Please contact me for more information on this point if you wish to derive very long period GDS transfer functions) Tellurometers: generally 100 m dipoles, Pb-PbCO4 electrodes, X-array configuration, contact to the ground ensured by using a conducting jelly (amorphous silicate, salt & water) sensitivity of typically 0.25 nV/km, Filters: HiPass -3dB points at 40 s LoPass -3dB points at 30000 s ***Additional HiPass filters on the telluric channels at both 1s and 10s. Thus there are three (3) HiPass filter stages, each of 2-pole Butterworth Recorders: DATEL cassette recorders with a 12 bit A/D timing (by an hour mark) to better than 20 s with less than 20 s drift over one week cassettes changed weekly (precise time of change available on request) Filters: 2-pole Butterworth filters with matched components such that the filters can be characterized to better than 1% by their -3dB points. See APPENDIX 1 for information on how to remove the filter response from the cross-spectra System Box: An aluminium box with 2 inches of insulation on the sides and bottom, and 4 inches of insulation on the top. Tests by Lawrie Law and Ron Kurtz indicate that this insulation is equivalent to about 1 - 2 feet of earth. SITE INFORMATION ================ Site MF1.01 (EMSL01); Drat Creek 44 54.2N 123 55.1W (10.6 km from coast) =============================================================================== Site located in a wood with head buried well and system box well shaded. Unfortunately there was a small prking area nearby (within 100 m) so that there may be very occassional noise on the magnetic channels due to traffic 18 July - 22 Sept continuous. Data of generally high quality with few problems, occassional offsets (See EMSL02). The following list gives on the first record:- (a) the station (EMSL01) (b) the time interval for which these calibration settings and filter -3dB points are valid (8507072345-8507180115) (c) the number of channels (5) (d) the MT system used (MT#9), (e) the magnetometer used (31) (f) the tellurometer used (0841) (g) the Datel used (1029) followed by five records, one for each component, giving:- (a) the component name (b) the calibration factor (NOTE: do not use as this data is in field values) (c) the LoPass -3dB point (d) the HiPass -3dB point (NOTE: no HiPass filters on magnetic channels) (e1) the magnetometer calibration factor, or (e2) the dipole length followed by the gain factor on the tellurometer (f) the Datel calibration factor EMSL01 8507072345-8507180115 5 020 MT#9 Mag:31 Tell:0841 Datel:1029 'H' 0.099906 42.8 0.0 Mag:0.0999360 Datel:0.9997779 'D' 0.100004 46.6 0.0 Mag:0.0999940 Datel:1.0005559 'Z' 0.100021 43.1 0.0 Mag:0.1000010 Datel:1.0001111 'N' 18.1745 45.9 31027.1 Ex:55m x1 Datel:0.9997779 'E' 15.3892 40.6 30840.7 Ey:65m x1 Datel:1.0003334 EMSL01 8507180116-8508132239 5 020 MT#9 Mag:31 Tell:0841 Datel:1029 'H' 0.099906 42.8 0.0 Mag:0.0999360 Datel:0.9997779 'D' 0.100004 46.6 0.0 Mag:0.0999940 Datel:1.0005559 'Z' 0.100021 43.1 0.0 Mag:0.1000010 Datel:1.0001111 'N' 0.181745 45.9 31027.1 Ex:55m x100 Datel:0.9997779 'E' 0.153892 40.6 30840.7 Ey:65m x100 Datel:1.0003334 EMSL01 8508132240-8508202238 5 020 MT#9 Mag:31 Tell:0841 Datel:1029 'H' 0.099906 42.8 0.0 Mag:0.0999360 Datel:0.9997779 'D' 0.100004 46.6 0.0 Mag:0.0999940 Datel:1.0005559 'Z' 0.100021 43.1 0.0 Mag:0.1000010 Datel:1.0001111 'N' 0.363490 45.9 31027.1 Ex:55m x50 Datel:0.9997779 'E' 0.307784 40.6 30840.7 Ey:65m x50 Datel:1.0003334 EMSL01 8508202239-8509222203 5 020 MT#9 Mag:31 Tell:0841 Datel:1029 'H' 0.099906 42.8 0.0 Mag:0.0999360 Datel:0.9997779 'D' 0.100004 46.6 0.0 Mag:0.0999940 Datel:1.0005559 'Z' 0.100021 43.1 0.0 Mag:0.1000010 Datel:1.0001111 'N' 0.181745 45.9 31027.1 Ex:55m x100 Datel:0.9997779 'E' 0.153892 40.6 30840.7 Ey:65m x100 Datel:1.0003334 Site MF1.02 (EMSL02); Gravel Creek 44 53.5N 123 46.5W (19.3 km from coast) =============================================================================== Site very isolated in a wood with the head well buried and the system box well shaded. 25 July - 22 Sept. missing 1 - 7 August. Many offsets in the data caused by sticking bits on the Datel recorder used. These offsets have been removed in an automatic manner by first-differencing, de-spiking, then first-integrating. This method looses the baseline such that successive cassettes of data may have a different "zero" line. Thus, if you intend to interpolate over a cassette change missing data interval, you must consider that there will probably be a "step" as well. EMSL02 8507082054-8508132134 5 020 MT#8 Mag:28 Tell:1334 Datel:1028 'H' 0.09995 41.3 0.0 Mag:0.0999980 Datel:0.9995558 'D' 0.09996 36.9 0.0 Mag:0.1000300 Datel:0.9993338 'Z' 0.09997 43.4 0.0 Mag:0.1000100 Datel:0.9995558 'N' 0.09996 36.8 30372.9 Ex:100m x100 Datel:0.9995558 'E' 0.12490 44.1 31322.0 Ey:80m x100 Datel:0.9992228 EMSL02 8508132134-8508202047 5 020 MT#8 Mag:28 Tell:1334 Datel:1028 'H' 0.09995 41.3 0.0 Mag:0.0999980 Datel:0.9995558 'D' 0.09996 36.9 0.0 Mag:0.1000300 Datel:0.9993338 'Z' 0.09997 43.4 0.0 Mag:0.1000100 Datel:0.9995558 'N' 0.09996 36.8 30372.9 Ex:100m x100 Datel:0.9995558 'E' 0.24980 44.1 31322.0 Ey:80m x50 Datel:0.9992228 EMSL02 8508202048-8509221934 5 020 MT#8 Mag:28 Tell:1334 Datel:1028 'H' 0.09995 41.3 0.0 Mag:0.0999980 Datel:0.9995558 'D' 0.09996 36.9 0.0 Mag:0.1000300 Datel:0.9993338 'Z' 0.09997 43.4 0.0 Mag:0.1000100 Datel:0.9995558 'N' 0.09996 36.8 30372.9 Ex:100m x100 Datel:0.9995558 'E' 0.12490 44.1 31322.0 Ey:80m x100 Datel:0.9992228 Site MF1.04 (EMSL04); Black Rock 44 51.2N 123 31.6W (40.0 km from coast) =============================================================================== Site located in an open old logging cut with is relativelt flat in the EW direction but does have a gradient estimated at some 4 m over the NS dipole. Thus there will be topographic effects on the Ex data. The head was reasonably well buried but the system box was exposed. 24 July - 22 Sept. continuous. High quality data with few problems. EMSL04 8507100209-8509221638 5 020 MT#11 Mag:34 Tell:50546 Datel:1031 'H' 0.10007 43.0 0.0 Mag:0.1000420 Datel:1.0003334 'D' 0.10003 46.5 0.0 Mag:0.1000000 Datel:1.0003334 'Z' 0.09994 42.5 0.0 Mag:0.0999300 Datel:1.0004447 'N' 0.10007 47.8 29694.9 Ex:100m x100 Datel:1.0006671 'E' 0.10001 41.5 30203.4 Ey:100m x100 Datel:1.0001111 Site MF1.05 (EMSL05); Bridgeport 44 50.1N 123 24.6W (48.9 km from coast) =============================================================================== Site located in a very flat marshy plain within a small valley. The head was reasonably well buried but the system box was exposed. This should of been named the "100 DOLLAR SITE" as that was the "fee" I had to pay for the use of the field. 17 July - 22 Sept. missing 24 - 31 July. Serious offsets as for Site EMSL02 EMSL05 8507102024-8508131743 5 020 MT#6 Mag:25 Tell:1331 Datel:1026 'H' 0.10011 42.0 0.0 Mag:0.1001542 Datel:0.9995558 'D' 0.09982 39.6 0.0 Mag:0.0998881 Datel:0.9993338 'Z' 0.10000 43.2 0.0 Mag:0.1000020 Datel:0.9998889 'N' 0.09999 45.8 30033.9 Ex:100 x100 Datel:0.9998889 'E' 0.09998 45.6 28135.6 Ey:100 x100 Datel:0.9997779 EMSL05 8508131744-8509220039 5 020 MT#6 Mag:25 Tell:1331 Datel:1023 'H' 0.10021 43.2 0.0 Mag:0.1001542 Datel:1.0005559 'D' 0.09998 48.7 0.0 Mag:0.0998881 Datel:1.0008897 'Z' 0.10011 44.4 0.0 Mag:0.1000020 Datel:1.0008897 'N' 0.10009 46.1 30033.9 Ex:100 x100 Datel:1.0008897 'E' 0.10020 47.0 28135.6 Ey:100 x100 Datel:1.0020040 EMSL06 8507110108-8507181830 5 020 MT#3 Mag:18 Tell:1321 Datel:1023 'H' 0.10002 43.2 0.0 Mag:0.0999600 Datel:1.0005559 'D' 0.10005 48.7 0.0 Mag:0.0999600 Datel:1.0008897 'Z' 0.10009 44.4 0.0 Mag:0.1000000 Datel:1.0008897 'N' 0.10009 46.1 30406.8 Ex:100m x100 Datel:1.0008897 'E' 0.10020 47.0 31966.1 Ey:100m x100 Datel:1.0020040 Site MF2.06 (EMSL06); Monmouth 44 49.2N 123 17.3W (58.8 km from coast) =============================================================================== Site located in an experimental tree station. Head under 2 feet of soil and system box exposed. 18 July - 22 Sept missing 25 - 31 July. Generally good data but with drifts in H & D that appear linear. Noisy during 23 - 27 August due to seeds being harvested off the trees. EMSL06 8507181831-8509212313 5 020 MT#2 Mag:18 Tell:1285 Datel:1022 'H' 0.09957 42.6 0.0 Mag:0.0999600 Datel:0.9961261 'D' 0.09951 37.6 0.0 Mag:0.0999600 Datel:0.9954651 'Z' 0.09956 47.9 0.0 Mag:0.1000000 Datel:0.9955752 'N' 0.09950 39.1 30576.3 Ex:100m x100 Datel:0.9950249 'E' 0.09950 42.7 29457.6 Ey:100m x100 Datel:0.9950249 Site MF2.08 (EMSL08); Looney Butte 44 45.9N 122 58.6W (84.1 km from coast) =============================================================================== Site located in the unused corner of a hay field. 18 July - 22 Sept. missing 24 - 30 July & 6 - 12 August. This part of the Willammette Valley is so populated that I had to come off-line to the South, and then had to use an unsatisfactory location just to the South of the outcropping Salem Hills (expect static-shift effects). The head was not well buried (the mud was like concrete to dig!) and John Booker later reburied it; and the electrode lines were as an L-array instead of the usual X-array configuration. The jelly may have dried out partially during the experiment, such that the ground contact resistance may have become very high. Use the telluric data with care; but the magnetic channels are OK. EMSL08 8507120343-8509212032 5 020 MT#7 Mag:27 Tell:1332 Datel:1027 'H' 0.09993 46.8 0.0 Mag:0.0998921 Datel:1.0003334 'D' 0.10010 43.1 0.0 Mag:0.1001041 Datel:1.0000000 'Z' 0.09982 46.8 0.0 Mag:0.0998163 Datel:1.0000000 'N' 0.12500 44.7 29355.9 Ex:80m x100 Datel:1.0000000 'E' 0.12504 46.1 30101.7 Ey:80m x100 Datel:1.0003334 Site MF2.10 (EMSL10); McCully Mtn 44 44.8N 122 38.2W (111.6 km from coast) =============================================================================== Site located on a flat large plateau with the head well buried and shaded, and the system box partially shaded. 23 July - 22 Sept. continuous but with a magnetometer change on 30 July. High quality data but with a non-linear drift in H. EMSL10 8507122143-8509022145 5 020 MT#5 Mag:24 Tell:1330 Datel:1025 'H' 0.09992 47.3 0.0 Mag:0.0999640 Datel:0.9995558 'D' 0.09984 41.3 0.0 Mag:0.0999201 Datel:0.9992228 'Z' 0.09993 48.7 0.0 Mag:0.1000260 Datel:0.9990010 'N' 0.09990 48.0 29525.4 Ex:100m x100 Datel:0.9990010 'E' 0.13145 40.5 30678.0 Ey:80m x100 Datel:0.9990010 EMSL10 8509022146-8509211821 5 020 MT#5 Mag:24 Tell:1330 Datel:1021 'H' 0.09996 47.0 0.0 Mag:0.0999640 Datel:1.0000000 'D' 0.09988 45.4 0.0 Mag:0.0999201 Datel:0.9995558 'Z' 0.10001 46.6 0.0 Mag:0.1000260 Datel:0.9998889 'N' 0.09999 45.2 29525.4 Ex:100m x100 Datel:0.9998889 'E' 0.13145 47.3 30678.0 Ey:80m x100 Datel:1.0002222 Site MF2.11 (EMSL11); Tom Rock 44 43.0N 122 27.6W (124.3 km from coast) =============================================================================== Site located within the confines of an experimental tree farm. Very well shaded and cool with the head well buried and the system box well shaded. 1 August - 21 Sept. continuous Offsets in the data removed automatically as for site EMSL02, also non-linear drifts in H. EMSL11 8507131928-8509211614 5 020 MT#1 Mag:08 Tell:1279 Datel:1034 'H' 0.10006 42.8 0.0 Mag:0.100046 Datel:1.0001111 'D' 0.10001 45.7 0.0 Mag:0.100000 Datel:1.0001111 'Z' 0.10005 42.8 0.0 Mag:0.100021 Datel:1.0003334 'N' 0.10001 41.0 30067.8 Ex:100m x100 Datel:1.0001111 'E' 0.10003 42.4 28339.0 Ey:100m x100 Datel:1.0003334 Site MF2.13 (EMSL13); Lucky Butte 44 37.9N 122 09.2W (146.3 km from coast) =============================================================================== Site located within in small copse of bushes in saddle-like topography (expect topographic effects). Head reasonably well buried (2 feet of soil) and system box shaded). 24 July - 21 Sept. continuous. Excellent high quality data EMSL13 8507150112-8507310235 5 020 MT#4 Mag:22 Tell:1329 Datel:MT-4 'H' 0.09999 48.5 0.0 Mag:0.0999660 Datel:1.0002222 'D' 0.10012 48.1 0.0 Mag:0.1000160 Datel:1.0010010 'Z' 0.09964 46.4 0.0 Mag:0.0995381 Datel:1.0010010 'N' 0.10537 46.7 29355.9 Ex:95m x100 Datel:1.0010010 'E' 0.11120 47.3 29898.3 Ey:90m x100 Datel:1.0007783 EMSL13 8507310236-8509201833 5 020 MT#4 Mag:38 Tell:1329 Datel:MT-4 'H' 0.10003 48.5 0.0 Mag:0.1000060 Datel:1.0002222 'D' 0.09999 48.1 0.0 Mag:0.0998861 Datel:1.0010010 'Z' 0.09964 46.4 0.0 Mag:0.0999780 Datel:1.0010010 'N' 0.10537 46.7 29355.9 Ex:95m x100 Datel:1.0010010 'E' 0.11120 47.3 29898.3 Ey:90m x100 Datel:1.0007783 Site MF2.14 (EMSL14); Bachelor Mtn 44 44.1N 122 03.8W (156.8 km from coast) =============================================================================== Site located on an open scrub brush clearing on top of a small rise (expect topographic effects). Head well buried and system box partially shaded. 24 July - 21 Sept. continuous. Strange H channel that goes "dead" for a while and then recovers and records properly. Could use H from EMSL13 instead. All other data fine. EMSL14 8507152003-8509201741 5 020 MT#10 Mag:32 Tell:1544 Datel:1030 'H' 0.09991 49.0 0.0 Mag:0.1000140 Datel:0.9990010 'D' 0.09987 47.5 0.0 Mag:0.0999920 Datel:0.9987792 'Z' 0.09964 48.3 0.0 Mag:0.0998183 Datel:0.9982254 'N' 0.12482 48.0 32389.8 Ex:80m x100 Datel:0.9985576 'E' 0.10550 46.5 30840.7 Ey:95m x100 Datel:1.0022272 APPENDIX 1 - Removal of system response from cross-spectra ========================================================== Note that because the -3dB points are occassionally below the Nyquist frequency, it is not possible to correct for the instrument response in the time domain. If you require this then you must apply the correction in the frequency domain, then inverse Fourier transform. LOW-Pass filter response removal -------------------------------- Assume we have a cross-spectra between the x & y components at period t (Sxy(t)), and that the x-channel & y-channel had -3dB low-pass filter points of tx & ty respectively. Then derive the corrected cross-spectra from:- Sr = real(Sxy(t)) Si = imag(Sxy(t)) Ax = 1. - (tx/t)**2. Ay = 1. - (ty/t)**2. Cx = 1.414*(tx/t) Cy = 1.414*(ty/t) CORRx = Ax*Ay + Cx*Cy CORRy = Ax*Cy - Ay*Cx X = CORRx*Sr - CORRy*Si Y = CORRy*Sr + CORRx*Si Sxy(t)_corrected = CMPLX(X,Y) HIGH-Pass filter response removal --------------------------------- The x-channel & y-channel have -3dB high-pass filter points of tx & ty respectively. Then derive the corrected cross spectra from:- Sr = real(Sxy(t)) Si = imag(Sxy(t)) Ax = 1. - (t/tx)**2. Ay = 1. - (t/ty)**2. Cx = -1.414*(t/tx) Cy = -1.414*(t/ty) CORRx = Ax*Ay + Cx*Cy CORRy = Ax*Cy - Ay*Cx X = CORRx*Sr - CORRy*Si Y = CORRy*Sr + CORRx*Si Sxy(t)_corrected = CMPLX(X,Y) APPENDIX 2 - Corrections applied to these data, noted errors, & missing data ============================================================================ The following corrections were applied to the Datel bits, not to the field data, and so to convert these corrections into field values you must:- (1) take the appropriate calibration factor given above, which convertd Datel mV into field values, (2) multiply this by 5000/2048, which converts the bits to mV & (3) multiply the magnetic components only by -1. This compensates for the Datel recorder having the highest order bits for negative voltages, which introduces a factor of -1 for all channels, and for the fact that we are recording potential differences, not electric fields themselves, which introduces a factor of -1 for the telluric channels only. Most corretions are for "offsets" caused by bit-sticking of the Datel recorders. For most recorders this is only a problem for the first hour after a cassette change, with the exceptions of EMSL02, EMSL05 & EMSL11 (see above). The corrections and comments are listed in order of site, then in order of the cassette number (basically week beginning 8507070000), then the start time of the hour, in format YYMMDDHHMM. An asterisk (*) following the start time indicates that the comments are for the whole of that cassette. The numbers given must be added (or subtracted) to the particular channel for the whole of the hour, given in the order of the five component (Hx, Hy, Hz, Ex, Ey). A correction of -9999 indicates that the data for that component for that hour was not worth retaining and has thus been deleted and is not subsequently included in this dataset. A marker of XXXXX indicates that the data for that component for that hour are known to be erroneous, but that they have been retained and are in these data. A "J" indicates that there are known offset jumps on that component for that hour. An "N" indicates known noise problems for that hour. A "+/-" indicates that the sign bit was considered to be in error. A "x" indicates missing data for that hour. STN tape hour corrections comments --- ---- ---- ----------- -------- EMSL01 02 8507180116 -512 -704 +512 0 -1024 1st hour 8507221016 0 +928 0 0 0 04 8507312238 +256 0 -256 +64 0 1st hour 05 8508062027 XXXXX 1st hour 06 8508132240 -9999 -9999 -9999 -9999 -9999 1st hour-gains altered 07 8508222138 J 08 8508272220 0 -128 -160 0 0 1st hour 09 8509031930 0 -192 0 0 0 1st hour EMSL02 02 8507172357* x x x x x tape inserted upsidedown 03 8507242214 -9999 -9999 -9999 -9999 -9999 1st hour NOTE: many offsets in data from this Datel have been removed automatically EMSL04 02 8507172128* x x x x x tape inserted upsidedown 03 8507241909 -9999 -9999 -9999 -9999 -9999 1st hour 04 8507311828 +949 -1632 +692 -177 -304 1st hour/no reset 05 8508061643 +430 +338 +305 0 0 1st hour 06 8508131743 +730 +624 +512 0 0 1st hour/no reset 07 8508201907 +1073 -2036 +248 +2013 0 1st hour 08 8508271907 +476 +752 +390 0 0 1st hour 09 8509031607 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 8509050807 0 -1000 0 0 0 10 8509091630 0 0 -137 0 0 1st hour 11 8509161730 +2817 +400 +404 0 +165 1st hour NOTE: there are some offsets in channel 5 (Ey) still in these data EMSL05 06 N broken telluric line NOTE: many offsets in data from this Datel have been removed automatically EMSL06 03 8507241745* x x x x x tape jammed 04 8507311727 -9999 -9999 -9999 -9999 -9999 1st hour 05 8508061510 -9999 -9999 -9999 -9999 -9999 1st hour 06 8508131610 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 07 8508201610 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 8508201610* N N N N N seeds harvested this week 08 8508271751 -9999 -9999 -9999 -9999 -9999 1st hour " N N Hx & Hy re-zeroed 09 8509031551 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 10 8509091451 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 11 8509160929 -9999 -9999 -9999 -9999 -9999 1st hour EMSL08 02 8507171705 -9999 -9999 -9999 -9999 -9999 1st hour 03 8507231803* x x x x x tape inserted upsidedown - 04 8507302019 -9999 -9999 -9999 -9999 -9999 1st hour 05 8508051919* x x x x x tape head not closed 06 8508121519* N N ground contact poor 8508161709 N N tellurics go off-scale 8508192219 -9999 -9999 07 8508192313 -9999 -9999 -9999 -9999 -9999 1st hour 8508192312* N N N N N fiels nearby ploughed 08 8508261606 -9999 -9999 -9999 -9999 -9999 1st hour 09 8509022042 -9999 -9999 -9999 -9999 -9999 1st hour 10 8509090042 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 11 8509152105 -9999 -9999 -9999 -9999 -9999 1st hour NOTE: the telluric data from this station must be analysed with care. Possibly a time-varying MT transfer function due to ground contact problems. EMSL10 02 8507130343* x x x x x tape inserted upsidedown 03 8507231818 -9999 -9999 -9999 -9999 -9999 1st hour 05 8508052132 -952 -407 -383 0 0 1st hour 06 8508121716 -1287 -866 -383 0 0 1st hour/no reset 8508121716* many errors in data 07 8508251244 -9999 -9999 -9999 -9999 -9999 8508251344 -9999 -9999 -9999 -9999 -9999 08 8508261838 -1393 -695 +348 0 0 1st hour 10 8509090003 +1152 -243 0 0 0 1st hour EMSL11 03 8507232144* x x x x x tape inserted upsidedown NOTE: many offsets in data from this Datel have been removed automatically EMSL13 02 8507162249* x x x x x tape inserted upsidedown 03 8507242149 -9999 -9999 -9999 -9999 -9999 1st hour 8507242149 mag fields suspect 04 8507310236 +2048 -1024 -1024 0 0 1st hour 8507310236* magnetometer changed 05 8508052236 -9999 -9999 -9999 -9999 -9999 1st hour/no reset 07 8508200256 0 -382 0 0 0 1st hour 08 8509030329 0 -403 -431 0 0 1st hour 09 8509030329 +/- -566 +/- 0 0 1st hour 10 8509061829 0 0 0 0 +1848 11 8509160042 0 +1024 0 XXXXX XXXXX 1st hour EMSL14 02 85071621??* x x x x x tape inserted upsidedown 04 8507310122 0 +768 0 0 0 1st hour 05 8508060017 +/- +/- 0 0 0 1st hour 07 8508231056 +1340 -280 +1374 0 0 8508250756 J J J J J 08 8508262205 -2048 0 0 0 0 1st hour " +/- 0 0 0 0 1st hour 11 8509160100 -9999 -9999 -9999 -9999 -9999 1st hour/no reset NOTE: the Hx channel goes intermittently "dead"