Seismic signatures: Small-scale features and ground fractures

Counts, Ronald C.; Obermeier, Stephen F.

doi:10.1130/2012.2493(10)

Cited by 8 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increasing width of the dikes with depth (Fig. 10) supports the interpretation of these dikes as having formed by the upward injection of sediment (Counts and Obermeier, 2012). The subvertical and planar morphology of the dikes at site 2 is consistent with the morphologies of the dikes documented at site 1.…”

Section: Interpretation Of Canterbury Earthquake Sequence Liquefactiosupporting

confidence: 71%

“…Liquefaction dikes are likely to preferentially form within loosely consolidated sands such as that within a paleochannel, as the sand provides a path of lower resistance compared to the surrounding silt. The site-specific depositional and hydrological conditions and the bulbous morphology of the oxidized feature are inconsistent with the liquefaction-triggering mechanisms and morphologies of nonseismic liquefaction features described in Montenat et al (2007), Owen andMoretti (2011), andCounts andObermeier (2012). This supports the interpretation that this oxidized lens and associated dike formed during a pre-Canterbury earthquake sequence earthquake.…”

Section: Interpretation Of Pre-canterbury Earthquake Sequence Liquefamentioning

confidence: 53%

“…The dike morphologies also do not correspond with the non-seismic soft-sediment deformation features outlined in Montenat et al (2007) and Counts and Obermeier (2012), further supporting the interpretation that the oxidized dikes were seismically triggered.…”

Section: (E) the Canterbury Earthquake Sequence Dike (Mx) Crosscuts Tmentioning

confidence: 76%

“…The increasing width of the dikes with depth suggests that these features formed by the upward injection of sediment, as opposed to downwardpropagating surface cracking, in which features would be expected to decrease in width with depth (Figs. 3, 4A, 4B, and 5; Counts and Obermeier, 2012). Individual dikes range in width from ~2 to 50 cm (Fig.…”

Section: Interpretation Of Canterbury Earthquake Sequence Liquefactiomentioning

confidence: 94%

“…Documentation of the subsurface features that fed known Canterbury earthquake sequence surface vents, and comparison with published photographs of subsurface liquefaction features aided the identification and interpretation of other liquefaction features that pinched out beneath the surface (see also Obermeier et al, 2005;Tuttle, 2001;Counts and Obermeier, 2012). High-resolution aerial photographs (flown on 24 February 2011 by NZ Aerial Mapping for the Christchurch Response Centre) were examined to identify the distribution of features at each site ( Fig.…”

Section: Trenchingmentioning

confidence: 99%

See 4 more Smart Citations

Paleoliquefaction in Christchurch, New Zealand

Bastin

Quigley

Bassett

2015

Geological Society of America Bulletin

View full text Add to dashboard Cite

Liquefaction during the 2010 moment magnitude (M w ) 7.1 Darfield earthquake and large aftershocks (known as the Canterbury earthquake sequence) caused severe damage to land and infrastructure in Christchurch, New Zealand. Liquefaction occurred at M wweighted peak ground accelerations (PGA 7.5 ) as low as 0.06g at highly susceptible sites. Trenching investigations conducted at two sites in eastern Christchurch enabled documentation of the geologic expressions of recurrent liquefaction and determination of whether evidence of pre-Canterbury earthquake sequence liquefaction is present. Excavation to water table depths (~1-2 m below surface) across sand blow vents and fissures revealed multiple generations of Canterbury earthquake sequence liquefaction "feeder" dikes that crosscut Holocene-to-recent fluvial and anthropogenic stratigraphy. Canterbury earthquake sequence dikes crosscut and intrude oxidized and weathered dikes and sills at both sites that are interpreted as evidence of pre-Canterbury earthquake sequence liquefaction. Crosscutting relationships combined with 14 C dating constrain the timing of the pre-Canterbury earthquake sequence liquefaction to post-A.D. 1660 to pre-ca. A.D. 1905 at one site, and post-A.D. 1415 to preca. A.D. 1910 at another site. The PGA 7.5 of five well-documented historical earthquakes that caused regional damage between 1869 and 1922 are approximated for the study sites using a New Zealand specific ground motion prediction equation. Only the June 1869 M w ~4.8 Christchurch earthquake produces a median modeled PGA 7.5 that exceeds the PGA 7.5 0.06g threshold for liquefaction. Prehistoric earthquakes sourced from regional faults, including the 1717 Alpine fault M w ~7.9 ± 0.3 and ca. 500-600 yr B.P. M w ≥ 7.1 Porters Pass fault earthquakes, provide additional potential paleoseismic sources for pre-Canterbury earthquake sequence liquefaction. The recognition of pre-Canterbury earthquake sequence liquefaction in late Holo cene sediments is consistent with hazard model-based predicted return times of PGAs exceeding the liquefaction triggering threshold in Christchurch. Residential development in eastern Christchurch from ca. 1860 to 2005 occurred in areas where geologic evidence for pre-Canterbury earthquake sequence liquefaction was present, highlighting the potential of paleoliquefaction studies to predict locations of future liquefaction and to contribute to seismic hazard assessments and land-use planning.

show abstract

Section: Interpretation Of Canterbury Earthquake Sequence Liquefactiosupporting

confidence: 71%

Section: Interpretation Of Pre-canterbury Earthquake Sequence Liquefamentioning

confidence: 53%

Section: (E) the Canterbury Earthquake Sequence Dike (Mx) Crosscuts Tmentioning

confidence: 76%

Section: Interpretation Of Canterbury Earthquake Sequence Liquefactiomentioning

confidence: 94%

Section: Trenchingmentioning

confidence: 99%

See 3 more Smart Citations

Paleoliquefaction in Christchurch, New Zealand

Bastin

Quigley

Bassett

2015

Geological Society of America Bulletin

View full text Add to dashboard Cite

show abstract

The problem of landscape evolution across the Cretaceous/Paleogene boundary revisited at Madrid East, southeastern Colorado, U.S.A.

Berry

2024

Cretaceous Research

View full text Add to dashboard Cite

Repetitive Late Pleistocene soft‐sediment deformation by seismicity‐induced liquefaction in north‐western Lithuania

et al. 2021

View full text Add to dashboard Cite

Liquefaction can cause deformation of unconsolidated sediment, but specific processes involved and the trigger mechanisms often remain obscured. This study describes multiple deformed sediment layers in a succession of lacustrine sand, silt and clay deposited during the Marine Isotope Stage 5d in north-western Lithuania. The deformation structures (load casts, pseudonodules, ball-and-pillow structures, broken-up laminae and injections) are embedded in ten separate layers of fine-grained, laterally continuous sediments. Detailed mesoscale sedimentological analyses suggest that each deformation event consisted of numerous successive stages of sediment advection facilitated by liquefaction. Low-permeability fine-grained laminae contributed to localized pore-water pressure build-up and lowering of sediment strength. Erosional top surfaces that truncate layers with soft-sediment deformation structures suggest that at least seven deformation events were separated by successive periods of initial erosion and then uninterrupted deposition in the lake. The most likely trigger of the deformation was recurrent palaeoseismic activity possibly linked to a late glacial isostatic adjustment following the Scandinavian Ice Sheet melting after the Saalian glaciation. This study emphasizes the potential role of seismic processes in shaping the sedimentary record of the intraplate region of north-eastern Europe and contributes to constraining the depth of liquefaction, regardless of the actual trigger mechanism.

show abstract

Seismic signatures: Small-scale features and ground fractures

Cited by 8 publications

References 0 publications

Paleoliquefaction in Christchurch, New Zealand

Paleoliquefaction in Christchurch, New Zealand

The problem of landscape evolution across the Cretaceous/Paleogene boundary revisited at Madrid East, southeastern Colorado, U.S.A.

Repetitive Late Pleistocene soft‐sediment deformation by seismicity‐induced liquefaction in north‐western Lithuania

Contact Info

Product

Resources

About