The U.S. Environmental Impact Statement (EIS), prepared for the military buildup, has some great summaries about Guam's environment. Most of this information reported is in the public domain and can be pieced together, but the EIS does a nice job of creating a narrative that gives some sense of the historical flow.
One source of information about Guam's earthquake history is the United States Geological Survey
Here's the EIS summary:
Guam experiences occasional earthquakes due to its location on the western edge of the Pacific Plate and near the Philippine Sea Plate. In recent years, earthquakes with epicenters near Guam have had magnitudes ranging from 5.0 to 8.7.
On October 30, 1936 (October 29, Universal Time), a magnitude 6.7 shock occurred about 80 mi (125 km) southwest of Guam. Walls were cracked and plaster and tile fell.T he seismic observer at Guam reported 25 tremors during the day of October 30. Another earthquake originated in the same area as the 1936 shock on September 16, 1970. The magnitude 6.2 tremor caused minor damage on Guam. A similar occurrence on November 1, 1975 (magnitude 6.2) produced damage on Guam that reached $1 million. The earthquake was felt strongly in many parts of the island.
On January 27, 1978, a magnitude 5.2 earthquake centered near the east coast of Guam caused considerable damage on the island. On August 8, 1993, the largest earthquake (magnitude 7.8) recorded on Guam occurred south of the Mariana Islands, injuring 48 people on Guam and causing extensive damage to hotels in the Tumon Bay area. Many landslides and rockslides were reported, mainly in the southern half of the island. The estimate of loss from damage to commercial buildings was placed at $112 million and loss from damage to private residences estimated at several million dollars.
I never much cared for Guam's Liberation Day celebration and in writing this I don't mean to marginalize the heroic sacrifice of U.S. troops in freeing the island from Japanese occupation. But the celebration always struck me as a bit much, considering Guam's history as a trophy possession by major powers. There are events of equal consequence to the people of this island, if not even more, that are given little attention. Most notably, is the turning over of Guam by Spain to the U.S. as part of the 1898 Spanish-American War settlement.
An interesting paper published in the Journal of Communication Inquiry looks at the role of the of the Pacific Daily News for this historical blindness. The author, Francis Dailisay of Washington State University, traveled to Guam to examine the newspaper archives and conclude that the newspaper is essentially a vehicle for reinforcing the American occupation and expansion.
Dailisay's analysis is a worthwhile read. For instance, even in those cases were the newspaper reported opposition to America's occupation ...
...the PDN found it necessary to reaffirm the actors’ loyalty to the United States. This was a strategy used by the newspaper to legitimize local dissenting opinions that challenged dominant American ideologies. These findings reveal how a local, mainstream newspaper in a U.S. colonial context presents the resistances of colonized actors within a socially controlled manner.
One conclusion is that the PDN has downplayed this conflict to foster U.S. control of the island.
Because the PDN was part of an American corporation (Gannett) at the time of this study, it may have chosen to do this in order to secure the continued flow of U.S. capital to Guam, which the PDN needed to support its daily news operations.
It's important to note that this paper's analysis concerns coverage over many years. Newspapers are fluid, living things and the philosophies and approaches of the current staff may not necessarily reflect historical patterns. Newspaper reporters, in my experience, are often the last people around to blindly accept authority. But this research paper, nonetheless, offers a means to assess the PDN's coverage. The work isn't available online and has to be purchased. Here's a link. It ought to be required reading in any newsroom considering anew: what does it mean to serve readers?