Before I talk about the credibility of both branches, let’s understand the basic difference between them. Geology is basically an observational science that tries to explain various phenomena and processes taking place at or near the surface of the Earth. On the other hand, Geophysics uses physical tools like Gravity, Potential, Seismic, Magnetic, etc. to study the interior of the Earth. It’s more like a branch of Geology itself. 

The coursework in Geological technology covers topics related to rocks, minerals, ores, volcanoes, mountains, oceans, glaciers, sediments, petroleum reservoirs, landslides, earthquakes, geoinformatics, and much more. The curriculum is similar to that of Applied Geology. The coursework in Geophysics comprises basic geological concepts along with detailed Geophysics concepts. Both branch students can opt for interdisciplinary courses as departmental electives. This initiative helps the students to gain an overall knowledge of Earth Sciences.

Placements-wise, both offer similar opportunities with the core recruiter being the same; the Energy Sector - Oil and Coal industry. Mineral exploration also offers core jobs to these two branches. The opportunities offered are equal and any difference stems from the individual's performance and not the branch’s credibility.

The majority of students are inclined towards research with the Geology students having an edge over Geophysical students in this aspect. For those seeking a management position or preparing for IAS, these two branches are the best owing to their light workload.

There are many reasons why I will suggest you to go for IIT Kharagpur for applied geology and exploration geophysics. Some of these reasons include,

• Being an older IIT, IIT KGP has a much broader alumni base than Roorkee which in turn proves to be useful for higher education. 
• In case you lose interest in Core geology you are always open to sitting for non-core placements which are in abundance at IIT KGP because of the alumni network.
• The curriculum at IIT KGP is way better than Roorkee in the sense that it is rigorous and much more industry relevant than Roorkee.
• IIT KGP has good administrative support and one can get funded for conferences.
• Being an MSc course, you can avail INSPIRE Scholarship given that you have a good GPA.

These points are more than enough of a deciding factor for you.