8.5 Commands in MULPLT, overview

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 

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.
          In multi mode: First left click gives start of zoom window. If
                followed by a left click, end of window is selected
                independent of mouse position. If first click is right
                click, start of window is selected.
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 amplitude  phase selected. Amplitude and period are 

A:        Automatic amplitude reading. 

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.
          Only in multi trace mode

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

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.
          If I is pressed again the synthetic arrivales are removed 
          and the iasp.out file is deleted.

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:        Make a spectrogram of all traces, multi trace mode only.

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: 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. Either all channels
          seen, one after the other or channels selected. 

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
Right and left mouse click: ----------------------
    In multitrace mode, the cursor must be between the 
       top frame and the menus or below lower x-axis
    In single trace mode, the cursor must be below upper trace window
    Remember, space bar is the same as left mouse click

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 
,: 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 

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 
                                                        jh 24-09-2021

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 (less than 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 '


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.

Displayeing epicentral or hypocentral distance

There is an option in MULPLT.DEF to plot epicentral or hypocentral distance on multi trace plots. The distanc is shown just after the DC and is given in km. The option is set with parameter PLOT DISTANCE. The default is not to plot distance.

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.

Figure 8.2: An example of using MULPLT in multitrace plot mode. Notice that start and stop times are different for different channels. The horizontal line at the start of the plot is the DC level. The small number above each trace to the right is the max absolute count with the DC-level subtracted and the small number to the left above the trace is the DC level. If plotting from EEV, the phase picks available are shown.

Figure 8.3: Examples of MULPLT with theoretical arrival times of some global phases. Short period seismograms are shown. The theoretical phases are marked with onset y below the trace and the read phases are marked normally above the trace.

Figure 8.4: Example of MULPLT with theoretical arrival times showing global phases on a long period seismogram. The filter used from 0.01 to 0.1 Hz. Without filtering, almost nothing would have been seen on this broadband station.

Figure 8.5: MULPLT in continous mode.
The plot shows 6 hours of long period data. The scale is 3000 counts between the traces and the filter used is from 0.01 to 0.1 Hz. The trace start time in hours and minutes is given on top of each trace. On the header line, P1 means the first page and DC is the DC level subtracted. Note that the numbers on the time scale at the bottom only are valid for the first trace unless all traces are 60 sec or 60 min long.

Figure 8.6: Example of the menu, which can be displayed on top of the plot. The current one might have different options.

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.

Multitrace mode:

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 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:

Channels are plotted by epicentral distance or in alphabetical order according to station name, see parameter NSORT_DISTANCE and CHANNEL SORTING in MULPLT.DEF. They can also be plotted in the order they are stored in the waveform file(s). By setting the channel order parameter in the MULPLT.DEF file, it is possible to plot the channels in distance or time order. If MULPLT is started from EEV (and NSORT_DISTANCE is set), the channels will be plotted in epicentral distance order unless the station if is not in the station file . If the event does not have an epicenter the location of the station with the first pick will be used as the epicenter for the ordering. 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. Ordering can be turned on with the key "-" or pressing (Dist). In this case distances are computed based on epicenter and station locations. 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 or archive

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.