This textbook is a written to support a course named ¿Geophysics 01¿ for the Geo-Measuring Engineering career, which is currently dictated by Jorge Reyes Molina in the Department of Geotechnical Engineering at University of Santiago (www.usach.cl). It is important to mention that Geophysics is a highly advanced science in Chile, due to the fact that Chile is the most seismic country of the world (e.g.: Earthquake 9.5 Mw of Valdivia , which occurred on May 22, 1960) and also because of the fact that Chile is the world's largest producer of copper (34% of world total). In this textbook the fundamental concepts of Geophysics and its connection to other areas of knowledge such as Geology, Physics and Civil Works are addressed. It must be noted that many of the topics addressed (as sections 1.1 , 1.3, 1.7, 1.8 , Chapter 2 , Chapter 3 , etc . ) match with the subjects studied in secondary education, which is why this textbook will be useful for a broad spectrum of readers.