Faults and Fluid Flow
Lead Research Organisation:
University of Strathclyde
Department Name: Civil and Environmental Engineering
Abstract
An integrated structural, petrological and isotopic study to examine fluid flow relations in the Highland Boundary Fault of Scotland.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509760/1 | 01/10/2016 | 30/09/2021 | |||
| 1904102 | Studentship | EP/N509760/1 | 01/01/2017 | 15/08/2021 | Lucy McKay |
| Description | Understanding the internal structure (i.e., fault core composition, width and geometry) of large faults is crucial because their fault structure and properties control how and where earthquakes occur. Compilations of data from multiple fault studies show that fault cores get wider on average with increasing total displacement (and hence slip events). However, the majority of faults in these datasets are from intraplate settings (faults within the interior of tectonic plates). Plate boundary faults have largely been excluded. As such there are no studies that systematically compare the two fault systems. This study aims to address this knowledge gap: compiling and harmonising a global dataset of intraplate and plate boundary fault core width and total displacement data in order to examine whether these fault systems evolve in a similar way with repeated slip events. The Highland Boundary fault (HBF), an ancient plate boundary fault in Scotland, is used as a field site to provide a case study for examining the internal structure and inferring the evolution of a plate boundary fault core. Detailed field, laboratory and mineralogical work reveal that the HBF core consists of four distinct units that remain unmixed. Not every unit is continuous along-strike and each unit varies in width (between 2.95 and 10.7 m). The units remain distinct as they formed at different stages of faulting and by different mechanisms affecting the faults ability to host earthquakes through time. For the first time, this work discovers quantitatively that plate boundary fault cores are narrower than predicted by the trend for intraplate faults and highlights that, for this reason, plate boundary faults do not dissipate as much energy as intraplate faults during earthquakes. These results are crucial for understanding the internal structure and evolution of plate boundary fault cores and have implications for understanding how earthquakes behave. |
| Exploitation Route | In the short-term: school children, teachers and the wider public. Earthquakes offer great potential to spark the interest of these users in Geosciences (and STEM subjects) and thus contribute to the UK's skillbase, notably in geophysics, an area with high industry demand and listed in the Home Office shortage occupation list. In the long-term: geologists and seismologists in government agencies and private companies responsible for earthquake monitoring and for seismic hazard and risk assessment, as a key element for assessing seismic hazard is to accurately predict ground motions, which requires a good understanding of earthquake physics and faults. Recently, several drilling projects have been undertaken at plate boundary faults (e.g., the San Andreas fault in California, Alpine fault in New Zealand and Nankai Trough in Japan) to determine how the internal structure of the fault influences earthquake behaviour. The main purpose of these projects is to predict and analyse future earthquakes. However, drilling is very expensive and effectively can only sample one or two boreholes, limiting the ability to capture the along-strike variation in fault zone properties. Our work therefore adds knowledge to the internal structure of seismological plate boundary faults, for which data is lacking, and helps understand how energy is partitioned along the fault during an earthquake. |
| Sectors | Energy,Environment,Other |
| URL | http://dx.doi.org/10.1144/jgs2018-226 |
| Description | William George Fearnsides Fund |
| Amount | £2,000 (GBP) |
| Organisation | Geological Society of London |
| Sector | Learned Society |
| Country | United Kingdom |
| Start | |
| Title | Data for: "Comparing fault core thickness, total displacement and earthquake properties between plate boundary and intraplate faults" |
| Description | A compilation of fault core thickness, total fault displacement and earthquake properties for plate boundary and intraplate faults in order to compare the two fault types. See the associated publication for more detail. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| Impact | Results published with Earth and Planetary Science Letters |
| URL | https://pureportal.strath.ac.uk/en/datasets/21271686-f115-4f9d-bf9a-ac681fd6f15b |
| Title | Structural and mineralogical data for the Highland Boundary fault |
| Description | The files in this dataset contain the structural and mineralogy data for the Highland Boundary fault (HBF). The dataset contains: (1) An excel spreadsheet containing the structural data for the Highland Boundary fault at Stonehaven, NE Scotland. This data was collected from fieldwork (geological mapping and structural logging) in 2017-2018. The metadata is described within the spreadsheet (metadata tab). (2) A pdf. file containing scanned copies of the structural logs that were used to collect some of the structural data contained within the spreadsheet. Other raw data is in field notebook format/map format and can be made available if requested (3) An excel spreadsheet containing the mineralogical data for the Highland boundary fault rocks. The metadata is described within the spreadsheet (metadata tab). The dataset relates to the EPSRC funded project with reference EP/N509760/1. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Impact | Data from this dataset was published in https://doi.org/10.1144/jgs2018-226 |