Details of Award
NERC Reference : NE/Z000394/1
Investigating mechanochemical tracers of seismic slip: IODP Exp. 405 JTRACK
Grant Award
- Principal Investigator:
- Dr CD Menzies, Durham University, Earth Sciences
- Grant held at:
- Durham University, Earth Sciences
- Science Area:
- Atmospheric
- Earth
- Freshwater
- Marine
- Terrestrial
- Overall Classification:
- Unknown
- ENRIs:
- Biodiversity
- Environmental Risks and Hazards
- Global Change
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Earthquakes
- Faulting
- Plate boundary tectonics
- Seismicity
- Subduction zones
- Geohazards
- Seismic hazards
- Seismicity
- Subduction
- Plate tectonics
- Tectonic Processes
- Earthquakes
- Ocean drilling
- Abstract:
- Large earthquakes in subduction settings rarely breach the sea floor, as the shallow portions of the fault mainly deform through non-earthquake creep processes. The 2011 Tohoku-oki earthquake (Mw 9.0), hosted on a subduction plate boundary fault, boasted the largest displacements ever recorded in an earthquake and initiated a catastrophic tsunami which devastated the northeast coast of Honshu, Japan. The earthquake was so damaging because the fault rupture propagated to the sea floor. It is therefore important to investigate the dynamic processes occurring during slip in these shallow sediments that host such earthquakes to enable us to understand why some earthquakes grow so large. The fault was drilled by IODP Exp. 343 JFAST, 13 months after the rupture and achieved partial recovery of the fault-zone. In September 2024, IODP Exp. 405 JTRACK will return to the site and aims to recover the full thickness of the fault-zone; drill undisturbed sediments across the trench for comparison; and install an observatory in the Well drilled through the fault-zone. When earthquakes occur, they impose brief but extreme conditions on local fault rocks which can drive mineralogical and mechanical properties change. This dynamic material evolution is a control for the ease of earthquake propagation and post rupture restrengthening of fault material. Exploring the mineralogical and chemical reactions that occur during and after an earthquake are therefore a target to help us understand how and why earthquakes, under some conditions, can grow to be very large and damaging. The mechanical energy released during an earthquake enables reactions that normally require high temperatures, to occur under low temperature conditions within shallow fault hosting sediments near to the seafloor. Investigating these so-called mechanochemical reactions and their transient products elucidates the dynamic frictional evolution of fault material and their role in enhancing or halting earthquake rupture. Reactions that occur during and after an earthquake rupture can be investigated by analysing the rock and the fluid present within the zones that slipped during an earthquake. An anomaly in oxygen isotopes has been found in another plate boundary fault setting and has been experimentally resolved to show it is a marker of seismic (fast) fault slip. This anomaly is a result of mechanochemical reactions allowing breakdown of clay minerals under lower pressure and temperature conditions than if burial alone was driving the reaction. A sediment transect analysing oxygen isotopes through the Tohoku-oki earthquake rupture surface will show if these reactions also occur in marine trench subduction settings. Fluids circulating the fault during and after the earthquake are also important to the frictional evolution of fault zone material and that can also be traced with this stable isotope analysis and geochemical modelling. Sediments cored away from the fault will be analysed to show the relative difference between deformed and undeformed units; with undeformed units being exposed to earthquake conditions in the lab to elucidate conditions necessary to synthesis the fault zone isotopic signature. The signatures of different reactions in our experimental set up will enable us to disentangle what we see in nature to allow us to identify processes that facilitate the generation of very large, damaging earthquakes.
- NERC Reference:
- NE/Z000394/1
- Grant Stage:
- Awaiting Event/Action
- Scheme:
- Directed (RP) - NR1
- Grant Status:
- Active
- Programme:
- UK IODP Phase4
This grant award has a total value of £25,077
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DA - Estate Costs | DI - Staff | DI - T&S |
|---|---|---|---|---|---|
| £5,598 | £255 | £269 | £42 | £10,231 | £8,681 |
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