The University of California-Santa Cruz (UCSC) High School Summer Internship (HSSI) in the Geo-Science program seeks to familiarize high school students with the process of scientific inquiry and encourage them to pursue careers in the geosciences through first hand experience with scientific research and interaction with role model mentors. The program enhances the process of learning science, exposes students to the excitement of doing science, and introduced them to the relevance of the geosciences to real-world problems and current issues. The summer experience will provide students with a strong foundation in the process of scientific research. Students participating in the HSSI program come from the diverse Santa Cruz and Pajaro Valley School Districts, which support 52% and 95% Latino/Hispanic students, respectively, many of whom are English language learners and/or students who receive free or reduced price meals. This two-year Track 1 pilot project is developing an inquiry-based geoscience education program to engage underrepresented high school students in a summer long, inquiry-based research program facilitated by graduate student mentors. During the pilot phase, 20 high school students - at least half of whom come from groups underrepresented in the geosciences - are being supported each year, and up to 20 graduate students each year will be engaged as mentors. Mentors are receiving pre-program training in mentoring and communication through a 2-day course built on the COSEE Communicating Ocean Science program. The project leverages resources and commitments to education and outreach at UCSC, including the Seymour Marine Discovery Center, a marine science center that communicates and explores ocean sciences research and societal issues with the public. The HSSI program is testing a new model for increasing the participation of underrepresented groups specifically in the geosciences by enlisting direct involvement and ownership of participating departments and their graduate students in the program and developing departmental recognition acknowledgment structures to reward graduate student participants who mentor the interns.