Carbon dating earthquakes
A geological study of the southern section of the Alpine Fault spanning the past years has given scientists an improved understanding of the behaviour of this major plate boundary fault. The investigation, which was centred on a remote river terrace near Lake McKerrow about 35km northeast of Milford Sound, and supplemented with information from the Haast area, found evidence of 24 surface ruptures of the Alpine Fault dating back to BC. Scientists used a range of investigation techniques, including radiocarbon dating of seeds, leaves, and reeds contained in swampy sediments, to determine the ages of the ruptures. The findings dramatically improve the known earthquake history of the Alpine Fault. Previously scientists had determined the ages for only the last four earthquakes dating back to about AD. The project has produced one of the longest continuous earthquake records of any on-land plate boundary fault in the world.
Is an earthquake behind carbon dating of Shroud of Turin image?
On the basis of geological, geophysical, and seismic data, we conclude that the recurrent normal faulting events within Aso caldera were triggered by the active faults of the HFFZ. As for the Kumamoto earthquake, seismic rupture initiated on the southwest side of the caldera, propagated northeastward, and terminated inside it. These findings demonstrate that large recurring earthquakes within an active fault-volcano system can be studied to improve our understanding of the termination of coseismic rupture propagation, and that the magma chamber beneath Mt.
Aso probably hinders the propagation of coseismic rupture during large earthquakes. Large recurring earthquakes generally occur on mature, active faults, and often accompany or precede volcanic eruptions 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8. Previous studies reveal that the M w 7. The newly formed coseismic ruptures under Aso caldera are considered to be potential new channels for magma venting, and these ruptures have changed the spatial heterogeneity and other mechanical properties of Aso volcano 3.
After the Kumamoto earthquake, Aso began to erupt on 8 October after 36 years of dormancy, suggesting a close relationship between volcanic eruptions and faulting in this case 4. Maps of the study area. Survey files of electrical resistivity and electromagnetic measurements; MTL: Honshu Island; Kyushu Isl.: Hinagu—Futagawa fault zone; Hinagu F: Hinagu Fault; Shirakawa F: Shirakawa Fault; Kurokawa F: Kurokawa Fault. Kurokawa R.: Kurokawa River. Ground deformation caused by the Kumamoto earthquake and seismicity in the area around the study region.
Also shown is the distribution of displacement along the coseismic surface rupture zone Surface displacement distribution data are from Lin 4 and deformation features caused by the Kumamoto earthquake are indicated data from Geospatial Information Authority of Japan Hinagu F: Hinagu Fault; Futagawa F: Futagawa Fault. Seismic data are from Sudo and Ikebe Kurokawa Fault; S. Shirakawa Fault. In this study, to better understand the relationship between the paleoseismicity and fault-volcano system structure, we conducted a comprehensive study of the active faults of the HFFZ—Aso volcano system.
This study is mainly based on field and trenching investigations, and radiocarbon dating ages for paleoseismic analyses, and geophysical surveys using electrical and electromagnetic methods, and seismic array observations for analyzing fault structures. The trench was excavated across the coseismic surface rupture produced by the M w 7.
Radiocarbon dating of samples was performed by accelerator mass spectrometry AMS by using bulk organic soils which were pretreated for excluding the modern plant carbon based on the Standard Pretreatment Protocols at Beta Analytic, USA. The electromagnetic measurements were carried out using an audio-magnetotelluric AMT method. Mount Aso, Japan is one of the largest active volcanoes in the world, with a caldera area of km 2. Subsequently, four large eruptions produced pyroclastic and lava flows across a wide area, including the study area Fig.
The Aso volcanic cluster comprises seven craters including Nakadake cone, which is the largest volcano within the caldera, and Komezuka and Kishima cones, which were ruptured by the M w 7. Two active faults have developed within Aso caldera; the NE-striking Kurokawa Fault part of which was previously called Nijutoge Fault 10 developed mostly along the Kurokawa River, on the western side of the caldera Fig. Within the caldera, coseismic surface ruptures related to the Kumamoto earthquake, that cut throughout the southwestern ring of the caldera, developed mainly along the Kurokawa Fault and are typically associated with coseismic graben structures 3 , 4 Fig.
Recent seismicity, including the and earthquake swarms within Aso caldera, is mainly concentrated along the Kurokawa Fault Fig. Seismic data indicate that the Kurokawa Fault is an active seismogenic fault that produces volcanic earthquakes within Aso caldera, which are mainly associated with normal faulting and volcanic activity due to a crustal heat source, i.
On the southwest side of Aso caldera, two other main active strike-slip faults have developed along the topographic boundary between the mountain to the southwest side and the Kumamoto Basin to the northeast: The M w 7. Coseismic graben structures have developed along the coseismic surface rupture zones produced by the Kumamoto earthquake on the western side of Aso caldera. The Kurokawa Fault is characterized by graben structures that were observed in trenches and fault outcrops at Locs.
Many fractures are found at the trench site in both horizontal excavation sections and trench walls, and they cut the near-surface soil layers and form graben structures Fig. Representative photographs of the Kurokawa Fault, showing normal fault structures. Sudo; b,c: Fault outcrop at Loc. Sketches of the exposed walls in Trench A. Microtremor array survey stations. See Fig. At Loc.
The fault cuts near-surface sedimentary layers of sandy soil and volcanic deposits, in which dark surface soil materials have been filled in fractures of the fault zone Fig. A trench was excavated across the coseismic rupture zone at Loc. The trench walls were sketched using a 1. S4 and are described in detail below. Dendrochronologically-calibrated calendar ages were obtained using the calibration method The deposits exposed in the trench include sandy soil, volcanic ash deposits, and fine-grained sand-silt that can be divided into 24 sedimentary units Units 0—23, Fig.
Units 0—8 consist of soil materials and volcanic sediments containing organic soils that are brownish-gray to dark gray in color and yield calibrated 14 C ages of AD — Fig. Unit 9 is composed of dark-gray soil materials and yields 14 C ages of AD — Units 10—22 consist of silt to fine-grained sand sediments with some dark gray soil materials, yielding 14 C ages of BC to AD Fig. All of these sedimentary layers are cut by faults F4 and F5. Liquefaction structures are observed in the sand sediment layers of Units 17—19 and Units 22—23 Fig.
These are discussed below. These observations indicate that a faulting event occurred after the deposition of Unit 9 AD —, AD — and before Unit 8 AD —, AD — , coincident with the normal faulting event inferred at Loc. Fault scarps at Loc. Bayesian model of paleoearthquake dates and inferred timing of faulting events.
Probability distribution functions PDFs for radiocarbon dating samples are shown in light gray and posterior PDFs are shown in dark gray. Modeled earthquake ages are shown as PDFs and labeled by event number. Lines below each distribution indicate the The penultimate faulting event E3 occurred during the deposition of units 11 and Fine-grained sand material was injected upward into the sand layer of Unit 12 along faults F4 and F5, these injection veins can be traced to the sand layers of Unit 17 with irregular boundaries Fig.
These upward-injected sand veins are in turn cut by the downward injection of veins of dark-gray surface soil formed along faults F4 and F5 by the Kumamoto earthquake Fig. These structural features show that the sand material of Unit 17 was liquefied and injected upward along faults F4 and F5 throughout the sand layers of units 16 and 13, and terminated inside the sediment layer of Unit 12, indicating a faulting-liquefying event occurred during the deposition of Units 11 and Such upward injection veins caused by paleoliquefactions have also reported in the seismogenic fault that triggered the — Canterbury earthquake sequence in Southwest Christchurch, New Zealand The development of a graben structure buried numerous remains, including pottery fragments, firestones, and other artifacts Therefore, we infer that this event resulted in the formation of the injection veins in units 12—17 at Trench A.
In the lowest parts of the trench walls, the sand material of Unit 23 is disturbed by irregular veins and lenses showing brownish- to yellowish-color within a zone bounded by faults F4 and F5 in units of 19 and 20 and overlain by the sand layer of Unit 18 Fig. These observations indicate the liquefaction of a sand layer in Unit 23 and that the liquefaction event E4 occurred in the period between Units 19—23 and Unit Furthermore, there is no evidence of surface ruptures with significant offsets caused by the four largest foreshocks and aftershocks M w 6.
Historical and paleoseismic studies have shown that the recurrence intervals of large earthquakes can be relatively well-constrained, thus providing the most direct measurements of recurrence intervals of moderate to large earthquakes along active faults 16 , 19 , Historical and instrumental records show that eight large earthquakes 6. Field investigations also confirm that the M w 6.
Two questions arise concerning the three large paleoearthquakes identified in this study. First, were the faulting events that offset the near-surface sediment layers triggered by faults within the caldera or in the HFFZ? Second, if the latter, did the seismic ruptures propagate northeastward across the caldera and terminate within it, as occurred during the M w 7. Field observations also reveal that the coseismic slip distribution along the fault shows an asymmetry pattern and that the coseismic surface ruptures occurred mostly along the Kurokawa Fault and are dominated by normal faulting with a maximum vertical offset of 1.
In the trench walls and outcrops, the vertical offsets of sedimentary units are observed, which are considered to be the component of net slips, because it is difficult to estimate the strike-slip component of motions within the caldera. Both ends of asymmetric fault slip distribution profile are considered to be initiation points of rupture and barriers where fault propagation is arrested It follows from first principles that neither coseismic faults nor fractures can develop in a magma chamber if the magma is in a liquid state 3.
Previous studies show that volcanic earthquakes can produce surface displacements accumulated on the faults that developed at shallow depths above the magma within the calderas 32 , In the study area, the Kurokawa Fault shows a straight linear trace, which also developed within Aso caldera. During the volcanic earthquake swarms occurred in November and March Fig. Recent trench investigations of the Hinagu and Futagawa faults reveal that i at least three morphogenic earthquakes prior to the Kumamoto earthquake occurring in the past years on the HFFZ Fig.
Accordingly, we suggest that the active faults of the HFFZ are the seismogenic faults that triggered the large paleoearthquakes; as in the case of the event.
Radiocarbon dating is a dating method that uses naturally occurring carbon atoms to determine the age of carbonaceous materials. Radiocarbon dating can . (xativacult.com) —An earthquake in Old Jerusalem might be behind the According to radiocarbon dating done in , the cloth was only
The evolution of paleoseismogeological studies clearly demonstrates that in order to properly understand the seismic potential of a region, and to assess the associated seismic hazard, extensive studies are necessary to take full advantage from the geological evidence of past earthquakes. The period of instrumental seismological observations is insignificant in comparison with the recurrence interval of strong earthquakes. Thus to achieve these goals the historical data are being involved. Paleoseismogeology supplements historical and instrumental records of seismicity by characterizing strong prehistoric earthquakes.
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A new study published in the journal Science , co-authored by University of Nevada, Reno's Glenn Biasi and colleagues at GNS Science in New Zealand, finds that very large earthquakes have been occurring relatively regularly on the Alpine Fault along the southwest coastline of New Zealand for at least 8, years. The team developed evidence for 22 earthquakes at the Hokuri Creek site, which, with two additional from nearby, led to the longest continuous earthquake record in the world for a major plate boundary fault. The team established that the Alpine Fault causes, on average, earthquakes of around a magnitude 8 every years.
Earthquake dating: an application of carbon-14 atom counting.
February 11, They believe that neutron radiation caused by an earthquake could have induced the image of a crucified man — which many people believe to be that of Jesus — onto the length of linen cloth, and caused carbon dating done on it in to be wrong. The Shroud has attracted widespread interest ever since Secondo Pia took the first photograph of it in According to radiocarbon dating done in , the cloth was only years old at the time. Other researchers have since suggested that the shroud is much older and that the dating process was incorrect because of neutron radiation — a process which is the result of nuclear fusion or nuclear fission during which free neutrons are released from atoms — and its interaction with the nuclei of other atoms to form new carbon isotopes.
Recurrent large earthquakes related with an active fault-volcano system, southwest Japan
This study builds upon previous investigations in order to develop a better chronology of large earthquakes generated by ruptures on the Alpine Fault. Work during the s has established that the Alpine Fault is a major source of potential seismic hazard and incorporation of data from the fault into seismic hazard maps has greatly changed the perception of earthquake hazard in the South Island. The Alpine Fault is a major potential seismic hazard throughout the South Island. Although this work has advanced our knowledge of the fault history, the questions raised at the start still require further research. Page last updated: Skip to main content. Google Tag Manager. You are here Home Research papers.
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.Carbon Dating - Example of exponential decay