Earthquake-induced Liquefaction Features Research Articles

The influence of sedimentary architecture on the formation of earthquake-induced liquefaction features: A case study in the New Madrid seismic zone

The influence of sedimentary architecture on the formation of earthquake-induced liquefaction features: A case study in the New Madrid seismic zone

Earthquake-induced liquefaction features in a late Quaternary fine-grained lacustrine succession (Fucino Lake, Italy): Implications for microzonation studies

The Fucino lacustrine basin in central Italy is a large flat area mostly devoted to agriculture, with urbanization along the perimeter of the ancient lake. In 1915 a strong earthquake struck the area (Mw 7.0), producing large damages and geological effects, including surface faulting, ground failures and liquefaction. A channel excavated in the lacustrine sediments exposed ground failure, with dykes of fine-grained sediment that we interpret as the result of earthquake-induced liquefaction. We present the results of a multidisciplinary work aimed at characterizing in detail the geology of the buried stratigraphic succession, its susceptibility to liquefaction and the likely source of the fine-grained liquefied material. The succession down to 20 m deep is formed by fine-grained sediments younger than ~170–180 kyrs (mostly Late Pleistocene - Holocene), prevailingly silt or silt-clay mixtures.

Late Pleistocene-Holocene earthquake-induced slumps and soft-sediment deformation structures in the Acequion River valley, Central Precordillera, Argentina

Abstract Evidence of earthquake-induced liquefaction features in the Acequión river valley, central western Argentina, is analysed. Well-preserved soft-sediment deformation structures are present in Late Pleistocene deposits; they include two large slumps and several sand dikes, convolutions, pseudonodules, faults, dish structures and diapirs in the basal part of a shallow-lacustrine succession in the El Acequión River area. The water-saturated state of these sediments favoured deformation. All structures were studied in a natural trench created as a result of erosion by a tributary of the Acequión River, called El Mono Creek. They form part of a large-scale slump system. Two slumps occur in the western portion of the trench and must have moved towards the ENE (70°), where the depocentre of the Boca del Acequión area is situated. Considering the spatial relationship with Quaternary faults, the slumps are interpreted as being due to a seismic event. The thickest dikes in the El Mono Creek trench occur in the eastern portion of the trench, indicating that the responsible earthquake was located to the east of the study area, probably at the Cerro Salinas fault system zone. The slumps, sand dikes and other soft-sediment deformation features are interpreted as having been triggered by earthquakes, thus providing a preliminary palaeoseismic record of the Cerro Salinas fault system and extending the record of moderate-to high-magnitude earthquakes in central western Argentina to the Late Pleistocene.

Geophysical Imaging of Subsurface Earthquake-induced Liquefaction Features at Christchurch Boys High School, Christchurch, New Zealand

On February 22, 2011, a magnitude Mw 6.2 earthquake affected the Canterbury region, New Zealand, resulting in many fatalities. Liquefaction occurred across many areas, visible on the surface as “sand volcanoes”, blisters and subsidence, causing significant damage to buildings, land and infrastructure. Liquefaction occurred at a number of sites across the Christchurch Boys High School sports grounds; one area in particular contained a piston ground failure and an adjacent silt volcano. Here, as part of a class project, we apply near-surface geophysics to image these two liquefaction features and determine whether they share a subsurface connection. Hand auger results enable correlation of the geophysical responses with the subsurface stratigraphy. The survey results suggest that there is a subsurface link, likely via a paleo-stream channel. The anomalous responses of the horizontal loop electromagnetic survey and electrical resistivity imaging highlight the disruption of the subsurface electrical properties beneath and between the two liquefaction features. The vertical magnetic gradient may also show a subtle anomalous response in this area, however the results are inconclusive. The ground penetrating radar survey shows disruption of the subsurface stratigraphy beneath the liquefaction features, in particular sediment mounding beneath the silt ejection (“silt volcano”) and stratigraphic disruption beneath the piston failure. The results indicate how near-surface geophysics allow the characteristics of liquefaction in the subsurface to be better understood, which could aid remediation work following liquefaction-induced land damage and guide interpretation of geophysical surveys of paleoliquefaction features.

Impact of earthquake-induced liquefaction and related ground failure on a Mississippian archeological site in the New Madrid seismic zone, central USA

An investigation of earthquake-induced liquefaction features and related ground failure at the East archeological site (3PO610) located near the southern end of the New Madrid seismic zone was crucial to the identification of cultural features and horizons and interpretation of archeological data. Through the examination of stratigraphic and structural relations in the archeological excavation as well as in three nearby trenches, it was determined that cultural horizons and features, including the floor of a sweat lodge, are tilted, displaced downward, and buried by a vented sand deposit, known as a sand blow. This sand blow is up to 1 m thick and is composed of four major depositional units, suggesting that it formed during a sequence of large earthquakes. The compound sand blow directly overlies cultural horizons and features, indicating that the earthquakes occurred near the end of or soon after occupation. On the basis of radiocarbon dating of samples collected above and below the sand blow, the earthquakes are estimated to have occurred between A.D. 1300 and 1670. A New Madrid earthquake sequence ca. A.D. 1450 ± 150 was the probable cause of liquefaction and ground failure at the site and may have led to cultural abandonment of the site. Ironically, the earthquakes that may have led to abandonment of the site also helped to preserve it for posterity.

Localization of Large Earthquakes in the Charlevoix Seismic Zone, Quebec, Canada, during the Past 10,000 Years

Earthquake-induced liquefaction features have been found in Holocene and Late Wisconsin sediments exposed along three rivers in the Charlevoix seismic zone. On the basis of their stratigraphic position and radiocarbon age constraints, the liquefaction features are thought to have formed during three or more earthquake episodes centered in Charlevoix during the past 10,000 years, including at least two prehistoric episodes approximately 5,000 and 10,000 years ago. The spatial distribution of liquefaction features coupled with liquefaction potential analysis suggests that the Charlevoix earthquakes were of moment magnitude ( M ) ≥ 6.2. Liquefaction features have not been found in similar sediments exposed along eight rivers in the Quebec City–Trois Rivieres area, 70 to 150 km from Charlevoix in the St. Lawrence River Valley. The apparent absence of liquefaction features in the Quebec City–Trois Rivieres area suggests that few, if any, large earthquakes have occurred here during the same time period. The geologic record of earthquakes may be incomplete in both areas due to fluctuations in Holocene sea level. Nevertheless, the rate of large earthquakes has apparently been much higher in the Charlevoix seismic zone than in adjacent areas of the St. Lawrence for thousands of years. These findings suggest that seismicity is localized in Charlevoix and that the presence of Iapetan rift faults that underlie the St. Lawrence Valley of southeastern Canada may not, in itself, indicate earthquake potential. These results may have important implications for other Iapetan rift faults in the eastern United States, as well as seismic source zone characterization and hazard assessment throughout eastern North America.

Very Large Earthquakes Centered Southwest of the New Madrid Seismic Zone 5,000-7,000 Years Ago

Earthquake-induced liquefaction features, including large sand blows, occur near Marianna, Arkansas, about 75 km southwest of Memphis, Tennessee, and 80 km south of the southwestern end of the New Madrid seismic zone. The Marianna sand blows formed between 5,000 and 7,000 years ago and predate paleoearthquakes attributed to the New Madrid seismic zone. The Marianna sand blows are similar in size to New Madrid sand blows, suggesting that they too formed as a result of very large earthquakes but were centered near Marianna and outside the New Madrid seismic zone. A large sand blow that formed about 3500 B.C. (5,500 years B.P.) may correlate with smaller sand blows to the northeast and southwest up to 175 km away. A compound sand blow that formed about 4800 B.C. (6,800 years B.P.) may have formed as the result of several very large, closely timed earthquakes. A fault zone associated with the eastern Reelfoot Rift margin seems the most likely source of large Middle Holocene earthquakes because of its great length (∼300 km), history of seismic activity, Late Wisconsin–Early Holocene fault movement in western Tennessee, and structural relationship to the New Madrid fault system. Additional study is needed to verify our initial findings, to identify the earthquake source, and to further define the earthquake potential of the Marianna area. If the eastern Reelfoot Rift margin were confirmed to be the source of Middle Holocene earthquakes near Marianna, seismicity would appear to vary in space and time within the Reelfoot Rift system. This would have important hazard implications for currently aseismic faults of the rift system and possibly of other aulacogens embedded in intraplate regions.

Three-Dimensional Imaging of Earthquake-induced Liquefaction Features with Ground Penetrating Radar Near Marianna, Arkansas

Ground penetrating radar (GPR) is a powerful tool used to study earthquake-related features such as sand blows and faults. The study area is near Marianna, Arkansas, and the work involves GPR surveys of large elliptical sand deposits. Our primary goal was to locate feeder dikes of sand blows and to image the contact between sand blows and the buried paleosurface in order to optimize the location of trenches. A secondary goal was to image the sand blows in three dimensions to define their sizes and morphology. Trenching large sand blows is costly and provides a limited view of the overall structure. GPR helps to identify possible locations for the venting dikes and to visualize the subsurface features. It also helps to map the locations in the sand blows of tree stumps that are useful for dating. The surveys imaged sharp contacts in near-surface sediments that were confirmed in trenches to represent boundaries between sand blows and buried soils. One survey in particular showed a sharp discontinuity in the boundary related to a large feeder dike. Because sand thickness was no more than 4 m, a 400 MHz antenna was used. This antenna is designed to provide high-resolution images of the upper 5 m of soil. Data acquisition was along parallel profiles oriented normal to the long axes of the sand deposits at all sites. Data reduction and analysis procedures included removal of direct and ground surface effects, frequency filtration, gain control, profile migration, and three-dimensional visualization. In future work, we plan to refine field procedures and test additional survey configurations to ensure the best results. We will survey additional sites to help with the follow-up trenching and sampling work.

Paleoliquefaction study of the Clarendon–Linden fault system, western New York State

The lack of earthquake-induced liquefaction features in Late Wisconsin and Holocene sediments in Genesee, Wyoming, and Allegany Counties suggests that the Clarendon–Linden fault system (CLF) did not generate large, moment magnitude, M ≥6 earthquakes during the past 12,000 years. Given that it was the likely source of the 1929 M 4.9 Attica earthquake, however, the Clarenden–Linden fault system probably is capable of producing future M ∼5 events. During this study, we reviewed newspaper accounts of the 1929 Attica earthquake, searched for earthquake-induced liquefaction features in sand and gravel pits and along tens of kilometers of river cutbanks, evaluated numerous soft-sediment deformation structures, compiled geotechnical data and performed liquefaction potential analysis of saturated sandy sediments. We found that the 1929 M 4.9 Attica earthquake probably did not induce liquefaction in its epicentral area and may have been generated by the western branch of the Clarendon–Linden fault system. Most soft-sediment deformation structures found during reconnaissance did not resemble earthquake-induced liquefaction features, and even the few that did could be attributed to non-seismic processes. Our analysis suggests that the magnitude threshold for liquefaction is between M 5.2 and 6, that a large ( M ≥6) earthquake would liquefy sediments at many sites in the area, and that a moderate earthquake ( M 5–5.9) would liquefy sediments at some sites but perhaps not at enough sites to have been found during reconnaissance. We conclude that the Clarendon–Linden fault system could have produced small and moderate earthquakes, but probably not large events, during the Late Wisconsin and Holocene.

The Earthquake Potential of the New Madrid Seismic Zone

The fault system responsible for New Madrid seismicity has generated temporally clustered very large earthquakes in A.D. 900 100 years and A.D. 1450 150 years as well as in 1811-1812. Given the uncertainties in dating liquefaction features, the time between the past three New Madrid events may be as short as 200 years and as long as 800 years, with an average of 500 years. This advance in understanding the Late Holocene history of the New Madrid seismic zone and thus, the contemporary tectonic behavior of the associated fault system was made through studies of hundreds of earthquake-induced liquefaction features at more than 250 sites across the New Madrid region. We have found evidence that prehistoric sand blows, like those that formed during the 1811-1812 earthquakes, are probably com- pound structures resulting from multiple earthquakes closely clustered in time or earthquake sequences. From the spatial distribution and size of sand blows and their sedimentary units, we infer the source zones and estimate the magnitudes of earth- quakes within each sequence and thereby characterize the detailed behavior of the fault system. It appears that fault rupture was complex and that the central branch of the seismic zone produced very large earthquakes during the A.D. 900 and A.D. 1450 events as well as in 1811-1812. On the basis of a minimum recurrence rate of 200 years, we are now entering the period during which the next 1811-1812-type event could occur.

Geophysical reconnaissance of earthquake-induced liquefaction features in the New Madrid seismic zone

Abstract Electrical resistivity and electromagnetic induction surveys performed at a site in the New Madrid seismic zone in the central United States demonstrate the ability of geophysical instrumentation to determine the location, size and orientation of earthquake-induced liquefaction features in the subsurface. Liquefaction features, including sand blows and sand dikes, are common within the Late Pleistocene and Holocene floodplain of the Mississippi River. These features and their relationship to host sediments provide important information about historic and prehistoric earthquakes and their source parameters, such as timing, epicentral location and magnitude. Following the geophysical surveys, two excavations were made and documented for a paleoseismic study. Sediment samples of soils, Native American occupation horizons, and liquefaction features within the trenches were collected for sedimentological and archeological analyses and compared with the geophysical observations. Measurements of the heights of cotton plants growing at the site were also taken, since growth appeared to reflect variations in the texture and thickness of soils developed on fluvial deposits and sand blows. The excavations, along with sedimentological and agricultural data, provided a means for calibrating sediment characteristics with the geophysical interpretations and for developing criteria to distinguish anomalies due to facies changes from anomalies related to liquefaction features. Disruption of the local sedimentological trends by an en echelon arrangement of sand dikes and related sand blows is seen in the combined geophysical and agricultural data. Results of the surveys indicate that constant-spread resistivity profiling (Wenner array) was an effective method for locating and mapping shallow sand dikes, some with widths of less than 50 cm. The electromagnetic induction method (EM-31), while less sensitive to dike locations, was useful in characterizing depositional facies changes by their differences in electrical conductivity. Data from the study site support the interpretation that the earthquake-induced liquefaction features occurred near the boundary of a facies change, which may have constituted a zone of weakness along which excess pore fluids and sand escaped.

Use of archaeology to date liquefaction features and seismic events in the New Madrid seismic zone, Central United States

Prehistoric earthquake-induced liquefaction features occur in association with Native American occupation horizons in the New Madrid seismic zone. Age control of these liquefaction features, including sand-blow deposits, sand-blow craters, and sand dikes, can be accomplished by extensive sampling and flotation processing of datable materials as well as archaeobotanical analysis of associated archaeological horizons and pits. This approach increases both the amount of carbon for radiocarbon dating and the precision dating of artifact assemblages. Using this approach, we dated liquefaction features at four sites northwest of Blytheville, Arkansas, and found that at least one significant earthquake occurred in the New Madrid seismic zone between A.D. 1180 and 1400, probably about A.D. 1300 ± 100 yr. In addition, we found three buried sand blows that formed between 3340 B.C. and A.D. 780. In this region where very large to great earthquakes appear to be closely timed, archaeology is helping to develop a paleoearthquake chronology for the New Madrid seismic zone. © 1996 John Wiley & Sons, Inc.

Use of archaeology to date liquefaction features and seismic events in the New Madrid seismic zone, Central United States

Prehistoric earthquake-induced liquefaction features occur in association with Native American occupation horizons in the New Madrid seismic zone. Age control of these liquefaction features, including sand-blow deposits, sand-blow craters, and sand dikes, can be accomplished by extensive sampling and flotation processing of datable materials as well as archaeobotanical analysis of associated archaeological horizons and pits. This approach increases both the amount of carbon for radiocarbon dating and the precision dating of artifact assemblages. Using this approach, we dated liquefaction features at four sites northwest of Blytheville, Arkansas, and found that at least one significant earthquake occurred in the New Madrid seismic zone between A.D. 1180 and 1400, probably about A.D. 1300 ± 100 yr. In addition, we found three buried sand blows that formed between 3340 B.C. and A.D. 780. In this region where very large to great earthquakes appear to be closely timed, archaeology is helping to develop a paleoearthquake chronology for the New Madrid seismic zone. © 1996 John Wiley & Sons, Inc.

The January 4, 1989, Earthquake in Bluffton, South Carolina, and its Tectonic Implications

Abstract An earthquake of magnitude 2.8 occurred on January 4, 1989, at 9:39:01.47 UTC (4:39 am EST) near Bluffton, in the lower South Carolina Coastal Plain, a region of low seismicity. More than seventy people in the Bluffton-Hilton Head area reported either hearing or feeling this early morning event. Historically, there have been three earthquakes, two of which had a MMI ≥ V, near Savannah, 25 km southwest of this earthquake. Recent discoveries of earthquake induced liquefaction features in the Bluffton area suggested that this area had been subjected to large ground motion in the past. Together, these data lead to the preliminary inference of a possible seismic source zone near Bluffton.

The southeastern Illinois earthquake of 10 June 1987: The later aftershocks

The 10 June 1987 southeastern Illinois earthquake ( mbLg = 5.2) was the seventh in a series of moderate magnitude (≧ 4.5) MMI VII shocks to occur in the Wabash Valley seismic zone of southeastern Illinois and southwestern Indiana since 1891. Located about 200 km east of St. Louis, Missouri, the shock caused minor damage in the epicentral area, had a contiguous felt area of about 433,000 km2, and had a total felt area over 1 million km2. Within 47 hours after the main shock, a cooperative effort between the U.S. Geological Survey and Memphis State University installed a 15-station aftershock monitoring network (later expanded to 21 instruments) that recorded more than 100 aftershocks in the following 4-day period. Results from the 56 aftershocks that were well located indicate a compact, cylindrically shaped aftershock volume about 1.7 km long, 0.8 km wide, and with a vertical distribution between about 9 and 12 km in depth. Composite focal mechanism solutions of the aftershocks suggest that the predominant mode of faulting is reverse slip, but some strike-slip type motion occurred similar to the mechanism for the main shock as determined from teleseismic data. The maximum principal compressive stress ( P axes) is oriented easterly to east-southeasterly and is subhorizontal in plunge. These results, combined with historical observations and the recent discovery of earthquake-induced liquefaction features in the area, imply that the seismic potential of the zone may be greater than generally perceived.

Evidence of Strong Earthquake Shaking in the Lower Wabash Valley from Prehistoric Liquefaction Features

Earthquake-induced liquefaction features in Holocene sediments provide evidence of strong prehistoric shaking, magnitude m(b) 6.2 to 6.7, in the Wabash Valley bordering Indiana and Illinois. The source of the one or more earthquakes responsible was almost certainly in or near the Wabash Valley. The largest event is interpreted to have occurred between 7500 and 1500 years ago on the basis of archeological, pedological, and stratigraphic relations.