To be a Geophysicist, a strong science background with an undergraduate degree with Physics and Mathematics is highly recommended. With an undergraduate degree, it is possible to opt for a Five Year Integrated M. Tech. Geophysical Technology at Department of Earth Sciences at Indian Institute of Technology, Roorkee, for which admission is obtained through Joint Entrance Examination (JEE). More opportunities exist to study Geophysics at the Masters and Ph.D. levels. For that, it is mandatory to acquire proficiency in Physics/ Mathematics or Geology at the Graduate level and then go for Masters in Geophysics. If you are not confident with Mathematics, still can get enrol for a graduation in Physics and then pursue a career as a Geophysicist. Educational qualifications in basic sciences will always offer opportunities in different areas, than specialized areas.
For example, earlier, Geophysics dealt with the measurements connected with the properties of Planet Earth and the quantitative studies related with the study of Earth's surface and core. For that matter, Geophysicists have equal expertise in exploring similar studies of all planetary bodies in the Solar System and beyond. For example, Dr. Krishan Khurana, who is a Research Geophysicist in the Institute of Geophysics and Planetary Physics and at the Department of Earth and Space Sciences at Uni. California, Los Angeles, has utilized induced magnetic fields to detect the presence of subsurface oceans on some of the satellites of Jupiter viz., Europa and Callisto. Europa is also astrobiologically significant! With your background in Biology and Physics can confidently undertake similar portfolio later in the career.