Advanced Exercise Solution 2a
from __future__ import print_function
from math import log10
from obspy import read
st = read("../data/LKBD_WA_CUT.MSEED")
tr_n = st.select(component="N")[0]
ampl_n = max(abs(tr_n.data))
tr_e = st.select(component="E")[0]
ampl_e = max(abs(tr_e.data))
ampl = max(ampl_n, ampl_e)
epi_dist = 20
a = 0.018
b = 2.17
ml = log10(ampl * 1000) + a * epi_dist + b
print(ml)