HAWC Observatory (IMAGE) Michigan Technological University Caption The HAWC Observatory sits at an elevation of 13,500 feet, flanking the Sierra Negra volcano inside Pico de Orizaba National Park in the Mexican state of Puebla. Its more than 300 water tanks can detect cascades of particles initiated by high-energy packets of light called gamma rays. Credit HAWC Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.