wiggle.m is used to plot seismic data using using wiggle or variable area type plotting, optionally on top of an image plot of the data wiggle type:

[Data,STH,SH]=ReadSegy('841_m.sgy','jump',10);
                      % get from 
                      % http://gdr.nrcan.gc.ca/seismtlitho/archive/le/stacks_fgp_e.php
wiggle([STH.TraceNumber],SH.time,Data,'wiggle',700);

Variable area:

[Data,STH,SH]=ReadSegy('841_m.sgy','jump',10,'minmax','TraceNumber',3500,4000,'trange',8,10);
wiggle([STH.TraceNumber],SH.time,Data,'VA',700);