Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin
Abstract Slow slip events (SSEs) have been identified at subduction zones globally as an important link in the continuum between elastodynamic ruptures and stable creep. The northern Hikurangi margin is home to shallow SSEs which propagate to within 2 km of the seafloor and possibly to the trench, p...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2022-02-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2021GC010107 |
| _version_ | 1797637986932752384 |
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| author | Srisharan Shreedharan Matt Ikari Clay Wood Demian Saffer Laura Wallace Chris Marone |
| author_facet | Srisharan Shreedharan Matt Ikari Clay Wood Demian Saffer Laura Wallace Chris Marone |
| author_sort | Srisharan Shreedharan |
| collection | DOAJ |
| description | Abstract Slow slip events (SSEs) have been identified at subduction zones globally as an important link in the continuum between elastodynamic ruptures and stable creep. The northern Hikurangi margin is home to shallow SSEs which propagate to within 2 km of the seafloor and possibly to the trench, providing insights into the physical conditions conducive to SSE behavior. We report on a suite of friction experiments performed on protolith material entering the SSE source region at the Hikurangi margin, collected during the International Ocean Discovery Program Expedition 375. We performed velocity stepping and slide‐hold‐slide experiments over a range of fault slip rates, from plate rate (5 cm/yr or 1.6 × 10−9 m/s) to ∼1 mm/s (10−3 m/s) and quantified the frictional velocity dependence and healing rates for a range of lithologies atdifferent stresses. The frictional velocity dependence (a‐b) and critical slip distance DC increase with fault slip rate in our experiments. We observe atransition from velocity weakening to strengthening at slip rates of ∼0.3 µm/s. This velocity dependence of DC could be due to a combination of dilatant strengthening and a widening of the active shear zone at higher slip rates. We document low healing rates in the clay‐rich volcaniclastic conglomerates, which lie above the incoming plate basement at least locally, and relatively higher healing rates in the chalk lithology. Finally, our experimental constraints on healing rates in different input lithologies extrapolated to timescales of 1–10 years are consistent with the geodetically inferred low stress drops and healing rates characteristic of the Hikurangi SSEs. |
| first_indexed | 2024-03-11T12:57:10Z |
| format | Article |
| id | doaj.art-0bb18ed92d154ca38bda871386dea332 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:57:10Z |
| publishDate | 2022-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-0bb18ed92d154ca38bda871386dea3322023-11-03T17:00:27ZengWileyGeochemistry, Geophysics, Geosystems1525-20272022-02-01232n/an/a10.1029/2021GC010107Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi MarginSrisharan Shreedharan0Matt Ikari1Clay Wood2Demian Saffer3Laura Wallace4Chris Marone5Department of Geosciences Pennsylvania State University University Park PA USAMARUM Center for Marine Environmental Sciences University of Bremen Bremen GermanyDepartment of Geosciences Pennsylvania State University University Park PA USAUniversity of Texas Institute for Geophysics University of Texas Austin TX USAUniversity of Texas Institute for Geophysics University of Texas Austin TX USADepartment of Geosciences Pennsylvania State University University Park PA USAAbstract Slow slip events (SSEs) have been identified at subduction zones globally as an important link in the continuum between elastodynamic ruptures and stable creep. The northern Hikurangi margin is home to shallow SSEs which propagate to within 2 km of the seafloor and possibly to the trench, providing insights into the physical conditions conducive to SSE behavior. We report on a suite of friction experiments performed on protolith material entering the SSE source region at the Hikurangi margin, collected during the International Ocean Discovery Program Expedition 375. We performed velocity stepping and slide‐hold‐slide experiments over a range of fault slip rates, from plate rate (5 cm/yr or 1.6 × 10−9 m/s) to ∼1 mm/s (10−3 m/s) and quantified the frictional velocity dependence and healing rates for a range of lithologies atdifferent stresses. The frictional velocity dependence (a‐b) and critical slip distance DC increase with fault slip rate in our experiments. We observe atransition from velocity weakening to strengthening at slip rates of ∼0.3 µm/s. This velocity dependence of DC could be due to a combination of dilatant strengthening and a widening of the active shear zone at higher slip rates. We document low healing rates in the clay‐rich volcaniclastic conglomerates, which lie above the incoming plate basement at least locally, and relatively higher healing rates in the chalk lithology. Finally, our experimental constraints on healing rates in different input lithologies extrapolated to timescales of 1–10 years are consistent with the geodetically inferred low stress drops and healing rates characteristic of the Hikurangi SSEs.https://doi.org/10.1029/2021GC010107slow earthquakesHikurangifrictionslow slip |
| spellingShingle | Srisharan Shreedharan Matt Ikari Clay Wood Demian Saffer Laura Wallace Chris Marone Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin Geochemistry, Geophysics, Geosystems slow earthquakes Hikurangi friction slow slip |
| title | Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin |
| title_full | Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin |
| title_fullStr | Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin |
| title_full_unstemmed | Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin |
| title_short | Frictional and Lithological Controls on Shallow Slow Slip at the Northern Hikurangi Margin |
| title_sort | frictional and lithological controls on shallow slow slip at the northern hikurangi margin |
| topic | slow earthquakes Hikurangi friction slow slip |
| url | https://doi.org/10.1029/2021GC010107 |
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