This trip took me back to the Philippines (where I lived in another life) to set up equipment to study a geothermal field near the town of Tiwi in the Albay province about 500 kilometers east of Manila.
The Albay province is a regular hot-bed of volcanic activity. It is home to the most active volcano in the Philippines, Mayon volcano, near the city of Legazpi. Tiwi is about 70km up the coast from Legazpi. When it's not raining Mayon is easily viewed from Tiwi. Tiwi is right next to a large volcano which is now extinct, but whose pool of magma is still relatively close to the surface. It is the heat from this magma that is used to create steam, and generate electricity.
The purpose of this experiment was to measure the micro-earthquakes (MEQs) produced when water is injected back into an area of hot rock that has been emptied of all of its water (in the form of steam). Measuring these MEQs will provide scientists with the means to determine where the water is going once it gets under ground, and determine what is happening to the underlying rock structure as it cracks because of the reintroduction of the water.