Brain Powered Vol 1

Brain Powered Vol 1 by Yoshiyuki Tomino. A Sci-Fi manga rated Teen, published in English by Tokyopop in 1998.

Earth has been ravaged by earthquakes and floods linked to Orphan, a gigantic alien craft buried beneath the Pacific. Agents called Reclaimers pilot living mechas known as Antibodies to recover the plates needed to revive it, a plan that would wipe out all life on Earth. When young Hime Utsumiya awakens a unique Antibody called Brain Powerd, former Reclaimer Yu Isami joins her to stop them. Based on the anime from Gundam creator Yoshiyuki Tomino.