Notable Events

The following is a collection of interesting, remarkable, or otherwise noteworthy seismic events, personally curated and annotated by our scientists

Magnitude 6.2 Omachi Earthquake

The M 6.2 Omachi earthquake occurred on Nov. 22, with a hypocentral depth of 10 km.

Drilling perturbation!

During IODP Expedition #348, we revisited and deepened riser drill site C0002N, located approximately 100 m East-Northeast of the observatory site C0002G. Pressures at the seafloor remain unchanged, whereas formation pressures exhibit a clear response to the drilling activity nearby. The response is complex, and include initial small increases in pressure (just prior to the large spikes in pressure highlighted here, and best viewed after removing the tidal signal), followed by large pressure spikes that decay over time. The large changes in pressure coincide with significant mud losses in the riser hole. We interpret the early response to reflect a typical response to fluid injection and pressure diffusion, whereas the latter responses likely indicate propagation of fracture and concomitant translation of pressure away from the riser hole. We are currently analyzing this response in more detail to quantify formation hydraulic properties.