Guest post by David Middleton
From Real Clear Science:
These 7 Expeditions Could Reveal Some of Earth’s Biggest Secrets in 2019
By Adam Mann
This past year brought tons of fascinating new information about our planet. But as scientists gaze into their crystal balls, they can see that this year is also sure to contain exciting surprises. Here we take a look at the seven most highly anticipated geophysics and Earth science expeditions, missions and meetings of 2019.
Inspecting Thwaites Glacier for cracks
Creating amazing new ice maps
Drilling into the cause of an earthquake
Off the southwest coast of Japan, deep below the Pacific Ocean, sits the Nankai Trough, an active subduction zone where one plate of the Earth’s crust is slipping beneath another. It is one of the most seismically active places on the planet, responsible for the 8.1-magnitude Tōnankai earthquake that rocked Japan in 1944. This year, the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) began drilling into the fault. It is the “first [expedition] to drill, sample and instrument the earthquake-causing, or seismogenic portion of Earth’s crust, where violent, large-scale earthquakes have occurred repeatedly throughout history,” according to the mission’s website. Rocks collected next year will be analyzed to see how slippery or solid they are, allowing researchers to “understand more about the conditions that might lead to an earthquake on these type of fault,” wrote team member John Bedford of the University of Liverpool on the expedition’s blog.
Measuring the forest and the trees
Exploring a buried Antarctic lake
Learning the history of coral reefs
Exploring the deep biosphere
Does anyone really care about cracks in the Thwaites Glacier or new ice maps? And pictures of trees taken from the ISS? Didn’t Landsat already do this sort of thing? Coral reefs are cool… But we already know their history, Maybe the history we know isn’t alarmist enough. Drilling into a subglacial lake is cool… unless they find The Thing.
Deep biosphere… Who cares? If you’ve seen one biosphere, you’ve seen them all. And, the deep biosphere is only a small piece of Deep Carbon 2019… Which is more of a convention than it is an expedition.
Now “drilling into the cause of an earthquake”… That’s really cool… Unless it triggers an earthquake. Technically the plan is to drill through the plate boundary in the Nankai Trough subduction zone. A fault system associated with massive earthquakes and tsunamis.
Nankai Trough Seismogenic Zone Experiment drilling expeditions have reached the final phase this October. About 11 years have passed since the first IODP (International Ocean Discovery Program) operation by D/V Chikyu cruise in September 2007. So far D/V Chikyu has completed 15 expeditions, 68 holes, and drilled a total length of more than 34 km. IODP Site C0002 has been attempted three times before (IODP Exps. 326, 338 and 348), in steps, finally reaching 3,058.5 mbsf (meters below sea floor) during 348. The objectives of IODP Expedition 358 are to penetrate toward 5,300 m, to cross the high-amplitude seismic reflector where the main plate boundary fault is believed to exist, crossing by Real-Time M-LWD (Measurement-Logging While Drilling) and WL (Wire Line) operation, monitor mud gas and cuttings, and limited core sampling of the ultra-deep fault zone. These operations are extremely difficult tasks never before achieved due to the fragile geological formation comprising the accretionary prism, and factors including the powerful Kuroshio current, location subject to typhoon approaches, and also affected by the passage of multiple cold fronts during the Winter months. This expedition is the culmination of over 20 years of planning and 11 years of IODP NanTroSEIZE drilling efforts to reach the plate interface fault system at seismogenic/slow slip depths.
The plan is to reenter the T&A’ed (temporarily abandoned) C0002F wellbore and drill to a depth of about 5,200 meters, where they expect to encounter the boundary between the Eurasian Plate and the subducting Philippine Sea Plate…
They will be running LWD (logging while drilling) tools to measure formation resistivity and natural gamma ray responses (just like we do in the real world), run wireline logs and core intervals above and in the plate boundary zone:
CDEX plans to implement IODP Expedition 358: NanTroSEIZE Plate Boundary Deep Riser 4, beginning on 7 October 2018. The main expedition goal is to deepen riser hole C0002F/N/P from 3000 mbsf to the primary megathrust fault target at ~5200 mbsf, using logging-while-drilling (LWD), downhole measurements, and drill cuttings analysis extensively, in addition to limited coring intervals. This expedition will be the culmination of 10 years of IODP NanTroSEIZE deep drilling efforts to reach the plate interface fault system at seismogenic / slow slip depths.
IODP Site C0002 is the deep centerpiece of the NanTroSEIZE Project, intended to access the plate interface fault system at a location where it is believed to be capable of seismogenic locking and slip, and to have slipped coseismically in the 1944 Tonankai earthquake. This drilling target also is in close proximity to the location where a cluster of very low frequency (VLF) seismic events and the first tectonic tremor recorded in any accretionary prism setting has been found, all suggesting fault processes related to the up-dip limit of megathrust seismogenic mechanics are active here.
◆StatusThe drilling operation passed a depth of 3058.5 m below seafloor, the former world record for the deepest scientific ocean drilling, on 3 December.
Data on formation properties of the geological strata have been successfully obtained by logging while drilling (LWD*).
*Measurement of formation properties such as resistivity and natural gamma ray while drilling using tools integrated into the bottom hole assembly.
Start: Move to Site C0002
Phase 1: BOP setting on the ocean bottom– After moving vessel to Site C0002, riser Hole F/N/P, launch ROV (Remote Operating Vehicle) with transponders. Deploy total of 10 transponders as an array on the sea floor.
– Retrieve corrosion cap, place corrosion cap beside the well head by ROV.
– Run BOP and Riser.
– On the rig floor, prepare drill and make up tools and check connections.
Phases 2 & 3: Ultra-deep drilling & Sample return from plate boundary
Phase 4: Onboard analysis
The Nankai Trough is known as a “Tsunami factory” and was the subject of a very detailed 3d seismic survey published in 2007 (Moore et al., 2007).
Moore et al., 2007 is available through Reaearchgate and was discussed in detail in Wired and University of Texas, Jackson School of Geosciences articles.
Who would have ever guessed that geology & geophysics can be fun and useful even when not applied to oil & gas exploration and production?
Moore, Gregory & Bangs, Nathan & Taira, Asahiko & Kuramoto, Shin’ichi & Pangborn, E & Tobin, Harold. (2007). Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation. Science (New York, N.Y.). 318. 1128-31. 10.1126/science.1147195.