Dr. Motonori Matuyama and Takamachi oil field

—A story about Japanese petroleum exploration in the past（part 7）—

Abstract

Although Dr. Matuyama had made two significant achievements, the discovery of negative gravity anormalies in the Japan Trench and the proposal of reversal magnetism in the earth's magnetic field, he was also a pioneer in the field of geophysical exploration in Japan.

The Takamachi oil field, the first successful case of applying a gravity survey to petroleum exploration in Japan, is a typical field with rapid development and depletion due to over drilling, but some subjects on its petroleum geology including subsurface geological structure remain to be not resolved.