Is this a sentence fragment?
Using instruments called geophones, scientists measuring seismic waves caused by traffic to learn how urban life affects the earth.
A: no
B: yes
This is a sentence fragment. It does not express a complete thought.
Using instruments called geophones, scientists measuring seismic waves caused by traffic to learn how urban life affects the earth.
Here is one way to fix the sentence fragment:
Using instruments called geophones, scientists have been measuring seismic waves caused by traffic to learn how urban life affects the earth.