How to plot the data spectrum raw?

Question

I am new in python and I need to plot the data spectrum of a earthquake. I have been reading a lot but I quite don't understand how to do it. I have been using and editing this code from library ObsPy

from obspy import UTCDateTime
from obspy.clients.fdsn import Client

t1 = UTCDateTime("2009-01-7T16:41:43.000")
t2 = UTCDateTime("2009-01-7T16:42:03.000")
fdsn_client = Client('IRIS')
# Fetch waveform from IRIS FDSN web service into a ObsPy stream 
#object
# and automatically attach correct response
st = fdsn_client.get_waveforms(network='G', station='HDC', 
                               location='00', channel='BHZ', 
                               starttime=t1, endtime=t2,
                               attach_response=True)

# define a filter band to prevent amplifying noise during the 
deconvolution
pre_filt = (0.005, 0.006, 30.0, 35.0)

st.remove_response(pre_filt=pre_filt, plot=True)

but this code plots a graph with the data spectrum raw, another with pre_filt applied and another graph with water lever applied (you can look the image link below). And I need to plot only the data spectrum raw (the top left graph of the image highlighted in a green rectangle), can someone help me how may I do it? I am a little bit bloked