When the trace(s) are on the screen and the cursor is displayed, then several options are available. Most options can be displayed by pressing the MENU button in the upper right hand corner. Pressing MENU again removes the option boxes. Commands can be given by either pressing a letter or clicking on a box in the menu (Figure 8.6 ). By pressing ? or clicking on the Help button, the following help menu will be displayed:
Help on MULPLT
MULPLT has 3 modes: multi trace mode: Displaying many traces, some picking options single trace mode: One trace, all picking options all channel mode: All channels for selected stations Most commands are given by pressing one key, however several commands can also be given by clicking in the appropriate menu box on top of the screen. If the full menu is not displayed, select the menu on top right part of the screen. The following commands are available, first given by the single letter command and if also available as a mouse click, the letters in the menu box is shown. COMMANDS ARE CASE SENSITIVE. Channel selection: In multitrace mode, one or several channels can be selected by clicking on the station code. Several channels can be selected by first clicking on first channel with left mouse button and then cliking on last chanel with right mouse button. If only one channel is selected, and toggl (t) to single trace mode is done, a new toggl in single trace mode will display all previous channels again. For the channels selected in multi channel mode, it is possible to change to single station 3-component mode with y and back again with y. If all channels from all stations shown in multi trace mode are desired, press u, back again with u or y. From single channel mode it is also possible to go to all channel mode for that station with y and back again with y. Two channels can be plotted on same trace with different colors. If the channel below is to be plotted on top the one above, the channel below is selected by putting cursor on channel and pressing & and then r for repolot. Zooming: Select a window with the mouse and a zoomed window will appear below in single mode and replace the plot in multi mode. In Single mode, it is also possible replot the zoomed window in place of the original by placing the cursor above the trace when selecting the zoom window. This makes it possible to zoom in the zoomed window. In order to go back to the original window in multi mode, do an opposite zoom, meaning picking the last point first. a: Read amplitude. Position cursor at the top of a wave and press a. Position cursor at the bottom of the wave and press a. Amplitude(0-p) and period are now stored. These values will be stored with the NEXT phase pick. Amplitude and period are displayed. A: Automatic amplitude reading, phase become AMP or read phase AMP but only after using a twice for reading amplitude. b: Filter 5-10 hz, see below B: Back Go back one trace in single trace mode From eev, multi: Go back one event Continous data base: Go back one window c: Read coda. C: Read end of coda automatically d: Delete phase. Position cursor near phase and press d. d: Del W: Delete waveform file(s), cursor outside area of trace plot, file(s) must be in working directory, else no files displayed. If done from EEV, only file names in S-file are deleted. D: Del S: Delete S-file if operated from EEV, multi mode e: Phase E E: Call external program (defined in MULPLT.DEF) to compute spectrogram. f: Next: Single: Go to next channel Multi, One event: Go to next event multi, continous data base: Go to next window F: FK: FK analysis of array data g: Groun: Make a ground motion seismogram(s). h: Azim: Make 3 component analysis (single mode ONLY) to determine azimuth of arrival. Select a window around the P-phase on the Z-component. Azimuth and apparent velocity will enter the S-file with the next phase reading. i: Phase I I: Iasp Calculate IASPEI synthetic arrival times, which are then displayed, multitrace only. For teleseismic events the IASP91 tables are used, while for local events the model defined in STATION0.HYP is used. j: mb: Generate a synthetic SP seismogram for reading amplitudes for determining mb. J: mB: Generate a synthetic BB velocity seismogram for reading amplitudes for determining mB. k: Ms: Generate a synthetic LP seismogram for reading amplitudes for determining Ms. K: MS: Generate a synthetic BB velocity seismogram for reading amplitudes for determining MS. l: Locat: Locate event, only multi trace mode m: Filter 15-24 hz, see below M: Merge: Merge waveform file, mulplt called from EEV, only if files are In working directory. n: Filter 10- 15 hz, see below. N: Toggle multiple windows to show all traces in one screen or one of the multiple windows. o: Oth C: Select other channels O: Out: Makes an output waveform file of current data on screen. Only multi mode. Response info not saved. Standard name with YYYY_MM... is used, name is written in text window. p: Regis: PUT (Register) event in database, you will be prompted for event type and waveform file will be copied to WAV. P: PartM Particle motion plot, requires the three components in multi trace plot q: Quit: Quit program r: Plot: Replot same event, useful when screen is cluttered up with e.g. many picks. Also used when a replot is wanted with new parameters e.g. filter. R: Change radius from epicenter or other selected point from which to select stations. s: Spec Make a spectrum, single mode ONLY. Press s, select window with cursor, answer questions and the spectrum will appear below with noise spectrum. S: Same as s without the noise spectrum, singel trace. S: Select station for area selection, only multi trace mode. t: Toggl: Toggle between multi and single mode T: OutW: Output file mulplt.wav of what is on screen u: Same as 'y' with the difference that all components for all stations are shown. U: Rotat: Rotate components. Backazimuth is calculated from location in header or as a second option, taken from observed + azimuth residual for respective station. R is plotted instead of N and T instead of E. Combining 3 component option (h) with u, the user is asked for the backazimuth angle. v: Filter 1-5 Hz, see below. y: AllC: Toggle to and from all channel mode. All channels are only for one station, for more stations use 'u'. Y: Pick a theoretical phase if displayed. Place cursor where the phase might be. Press y and the program will select nearest synthetic phase. w: WA: Remove system response and display synthetic Wood-Anderson ground motion in nanometers (nm) on next plot (using R or zoom). W: Oth W: Select other waveform file, same event z: Filter 0.001 to 0.1, see below x: Filter 0.1 to 1.0 Hz, see below Z: <W> Increase window length in plotting from a continous data base X: >W< Decrease window lenght when plotting from a continous data base >: Print: Will make a hardcopy of all channels of current event with the last selected filter, only in multitrace mode. <: Same as D *: Scale: Fixed scaling of trace amplitudes. Up and down arrows: Increase and decrease amplitude Horizontal arrows: Scroll _: Dist: Select plotting channels in distance order. : Resp: Plot response file, single trace mode only. TAB: NextW: Next window if multiple windows Filter options: The fixed filters (4/8 pole Butterworth) are placed on keys z,x,v,b,n,m with the following frequencies: z: 01-.1: 0.01 - 0.1 Hz Pressing key once gives a 4 pole filter one way x: .1-1.: 0.10 - 1.0 Hz Pressing the key twice, and the filter also v: 1 - 5: 1.0 - 5.0 Hz go the other way and it is now an 8 pole filter. ; 2 - 4: 2.0 - 4.0 Hz b: 5-10 : 5.0 - 10.0 Hz From menu, only 4 pole filters are used. n: 10-15: 10.0 - 15.0 Hz m: 15-23: 15.0 - 23.0 Hz .: Filt: Variable filter, question of filter limits is given in text window. ,: FixF Fix filter. If pressed aftrer selecting as filter, the filter remains fixed until pressing ',' again. ' Variable filter also with number of poles & Overlay, see in beginning of help section. Phase picking: This is possible in both modes. In Single mode, the phases defined are shown on top with some of the options, while they are not shown in Multi mode, but have the same definitions. Combining options: Note that you can select several options together. E.g. V and S will first filter the signal and then make the spectrum. Saving observations: When you go to the next trace or another event (F), the readings are saved in the S-file. They are also saved when you pick the next trace in Multi mode. This is also true for spectral parameters and azimuth determination. jh 25-2, 2016
Filters in MULPLT
All filters in MULPLT are Butterworth filters in time domain. When a filter is selected. using a hotkey or from the menu, the filter is only run one way, forward in time, and the number of poles is then 4. This will make a small phase delay where the first onset might appear a bit later, so if possible, read on unfiltered traces. If a 2 way filter is desired, press the filter key twice and the filter will also run backwards in time and the filter will be similar to an 8 poles filter. This gives theoretically a zero phase shift filter, however in practice, some of the onset energy is seen well before the first arrival, so it seems to distort the arrival times much more than using the 4 pole filter. When the program asks for a non fixed filter like when using the "." (Filt) command, the filter is always 4 poles by default. However, it is now also possible to interactively select number of poles and number of passes (1: forwards, 2: both ways) using the ' command. Press ' and the user is asked for filter frequencies, number of poles (<10, but more then 4 and the filter might become unstable for high sample rates) and number of passes. In addition LP (low pass), HP (high pass) and BR (band reject) filters can be used. E.g for a 5-10 Hz filter some of the choices are:
5 10 4 pole band pass, command . 0 10 4 pole low pass, command . 10 0 4 pole high pass, command . -5 10 4 pole band reject, command . 5 10 2 2 pole band pass, command '
WHEN PLOTTING, THE FILTER LIMITS, NUMBER OF POLES AND NUMBER OF PASSES IS WRITTEN ON THE SCREEN.
For band pass filters, the number of poles for both frequencies is the same. When doing spectral analysis or response removal and specifying a filter before, the filtering is done in time domain and the filter has the number of poles specified by the user, default 4. NOTE:When reading polarities, DO NOT USE FILTER, if possible.
Filtering and instrument correction: Since filtering is done in time domain, there is an added stability filter in frequency domain to avoid low frequency blow up. This filter is a 4 pole HP filter at 1/5 the filter low frequency corner.
Filter limitations: For frequencies below 0.5 Hz, only 4 pole BP and BR filters can be used. If the user try to select another number of poles, the number of poles is set to 4.
Filtered output: Extracting data with WAVETOOL, option 'Out'. It is only possible to use 4 pole BP filters, forward in time, using any other filter and the data is not filtered. Using option OutW any filter can be used but then only Ascii Helmberger format is possible. WAVETOOL can then convert to any other desired format.
Prior to version 9.1 MULPLT used a 4 pole Butterworth filter in time domain and an 8 pole Butterworth filter in frequency domain. The filters in frequency domain were use in connection with instrument response correction and spectral analysis. It has turned out that the frequency domain filters distorted the signal in some cases, particularly for narrow band and low frequencies. Therefore, frequency domain filters are no longer generally used. The change in filter setup, might change Ml magnitudes by 0.05 to 0.1 depending on which filter (if any) was used.
Displaying uncertain time
In each trace header in the SEISAN waveform file, there is a flag to indicate if the time might be uncertain (see Appendix B). If that flag has been set, the message `UNCERTAIN TIME' will be displayed on top of the trace. Currently this flag is only put into the waveform files if the data comes from a SEISLOG system that has detected a timing error or if the data is converted from SEED/MiniSEED data. Simlarly plotting SEED/MiniSeed data, uncertain time will be displayed if that flag is set in any block in the time window read in for a particular trace.
Below is some more detailed description of some of the options. The one letter command is given with the menu command in parenthesis:
To apply filters, first make a selection of options (filter, window, channel selection) and then execute by pressing R(Plot) (or selecting a zoom window). Figure 8.2 shows an example.
Single trace mode:
In this mode, one trace is initially displayed on top of the screen, see example on Figure 8.7. The traces used are the ones earlier selected and will be displayed one by one. Several options are now possible as can be seen on the menu. Normally no hardcopies are made in single trace mode since it is intended for fast routine work. However, by starting MULPLT in multitrace mode (option 2) and then go to single trace mode (command T(Toggl)), hard copy files are made.
In this mode hard copies can be made. If option 2 is used, both screen plot and hard copy files are made. If replot is made, only the last plot is available in the hard copy file. If option 3 is used, which is only hardcopy, there will be additional questions about, window length, start time, scaling and filters. If the scaling is set so that the plot occupies more than one page, several pages will be printed. If in this mode, filenr.lis is given as file name, the program assumes that all the files should be plotted and the only questions will be about the scaling and filters. All channels in each file will be plotted. This option is useful for plotting a large number of events with a single command.
All channel mode
In this mode, all channels for selected stations are displayed in a new window. This mode is particularly useful for working with three component data. By selecting one or several stations in multrace mode, all components for those stations will be displayed in new window by pressing y or ALLC on menu. Similarly in single trace mode, prsssing y or ALLC will display all channels for that station. The user can then go back to e.g. multitrace window and select another station to work with in three component mode.
Multiple screens in multitrace mode
If many channels are available (like more than 30), it might be difficult to distinguish all and the channels can be displayed in multiple screens. The number of channels per screen is set in MULPLT.DEF. The number of windows or screens for a particular data set is given in top left hand corner as e.g. `Win 2 of 7' meaning current window is number 2 of 7 windows. To move to the next window, use TAB or NextW in menu. In each window, normal operation can be done. Channels selected will be kept. Using a large data set, the user can then view each window separately, select the channels of interest and when all channels have been viewed, only the selected channels will remain for display. It is possible to togle between showing all channels and multiple screens by pressing N.
Plotting stations in a given distance range When many stations are available, it might be useful to only plot only the stations nearest the epicenter or a particular location. For this option to work, parameter MULPLT AREA in MULPLT.DEF must be set to a value larger than 0.0. for more information, see section Working with many channels in MULPLT"
Channel order in multitrace mode:
Normally channels are plotted in alphabetical order according to station name, see parameter CHANNEL SORTING in MULPLT.DEF. They can also be plotted in the order they are stored in the waveform file(s) (option NSORT_DISTANCE set in MULPLT.DEF). By setting the channel order parameter in the MULPLT.DEF file, it is also possible to plot the channels in distance or time order. If MULPLT is started from EEV (and distance ordering is set), the channels will be plotted in distance order provided distances are given in file. . Since there is no consideration for channels for the same station, the channels for one station, will be plotted in the same order as given in the waveform file. If a station is not found in the S-file, it will be plotted last. If plotting is done with MULPLT directly with a waveform file, the plotting order will be the start times as given in the waveform file header. Channel ordering can be turned on with the key "-" or pressing (Dist). If set in the MULPLT.DEF file, it is set when MULPLT starts up. It cannot be turned off for a given event when set from MULPLT but the flag is returned to the default value for the next event.
Plotting from continuous data base
If a continuous data base is set up (see section 2.2.3), it is then possible to plot all traces from the continuous data base with MULPLT. When MULPLT starts up, use option cont and the user is prompted for a start time and interval. MULPLT will now check all continuous data bases for available data in required interval and display the available data. The forward (next) or back option will display previous or next window respectively. There is an 25 % overlap between windows. If no data is available for the whole window, no trace is shown. If the beginning and the end is available, a line will join the two segments. If only end or beginning is available, only the available data is shown. All normal operation can be done on the window plotted so it is possible to e.g. extract data. If the register option is used, the whole window is extracted from the continuous data base as one file, copied to WAV and the S-file created.