Otago researchers reveal impact of ancient earthquake
IMAGE: THE RAISED ‘BENCH’ ABOVE THE WATERLINE AT RARANGI WAS ORIGINALLY FORMED AT SEA LEVEL BUT WAS UPLIFTED BY EARTHQUAKE ACTIVITY. view more
CREDIT: UNIVERSITY OF OTAGO
By combining the scientific powerhouses of genetics and geology, University of Otago researchers have identified a new area of coastal uplift, which had been hiding in plain sight.
The previously unknown region of earthquake uplift, in Rarangi, Marlborough, was discovered using a combination of new data from laser mapping and kelp genetics.
Co-author Professor Jon Waters, of the Department of Zoology, says the study gives new insights into the changes in Aotearoa’s landscapes and the recent history of earthquake impacts.
“In a geologically well studied country like New Zealand, there is still a lot to learn about our history of earthquakes and changing landforms,” he says.
The paper, just published in Journal of the Royal Society Interface, utilised LiDAR mapping (remote sensing technology used to model ground elevation) and genetic analysis of bull kelp from the uplifted section of coast.
The team identified a previously unrecognised area of uplifted rocky coastline – a bench about 1m above sea level – and a genetic anomaly in kelp below that bench. The kelp’s genetics indicate the species went extinct in the area following an earthquake, before being recolonised by kelp which drifted from 300km south.
The group believe the earthquake responsible occurred about 2000 to 3000 years ago, showing the potential for kelp to record geological disturbance events.
“The area is close to a well-known active fault and several big, past earthquakes have been well quantified by other researchers, but this coastal uplift zone was not previously known – the evidence for it is extremely clear now we’ve had a chance to look more closely.
“Rarangi is also a very popular summer swimming spot, rather than some obscure or remote location, and the evidence of coastal uplift was hiding in plain sight,” Professor Waters says.
The research is the latest output from the group’s Marsden-funded project assessing earthquake impacts on coastal species.
“Our work uses a combination of genetics and geology, and it’s quite exciting that these combined approaches have allowed us to pinpoint a previously unknown site of coastal uplift in New Zealand.
“This work serves to highlight again just how dynamic our country is – and how earthquake uplift leaves long lasting signatures in our coastal species.”
By combining the scientific powerhouses of genetics and geology, University of Otago researchers have identified a new area of coastal uplift, which had been hiding in plain sight.
The previously unknown region of earthquake uplift, in Rarangi, Marlborough, was discovered using a combination of new data from laser mapping and kelp genetics.
Co-author Professor Jon Waters, of the Department of Zoology, says the study gives new insights into the changes in Aotearoa’s landscapes and the recent history of earthquake impacts.
“In a geologically well studied country like New Zealand, there is still a lot to learn about our history of earthquakes and changing landforms,” he says.
The paper, just published in Journal of the Royal Society Interface, utilised LiDAR mapping (remote sensing technology used to model ground elevation) and genetic analysis of bull kelp from the uplifted section of coast.
The team identified a previously unrecognised area of uplifted rocky coastline – a bench about 1m above sea level – and a genetic anomaly in kelp below that bench. The kelp’s genetics indicate the species went extinct in the area following an earthquake, before being recolonised by kelp which drifted from 300km south.
The group believe the earthquake responsible occurred about 2000 to 3000 years ago, showing the potential for kelp to record geological disturbance events.
“The area is close to a well-known active fault and several big, past earthquakes have been well quantified by other researchers, but this coastal uplift zone was not previously known – the evidence for it is extremely clear now we’ve had a chance to look more closely.
“Rarangi is also a very popular summer swimming spot, rather than some obscure or remote location, and the evidence of coastal uplift was hiding in plain sight,” Professor Waters says.
The research is the latest output from the group’s Marsden-funded project assessing earthquake impacts on coastal species.
“Our work uses a combination of genetics and geology, and it’s quite exciting that these combined approaches have allowed us to pinpoint a previously unknown site of coastal uplift in New Zealand.
“This work serves to highlight again just how dynamic our country is – and how earthquake uplift leaves long lasting signatures in our coastal species.”
JOURNAL
Journal of The Royal Society Interface
ARTICLE TITLE
Integrating kelp genomic analyses and geological data to reveal ancient earthquake impacts
ARTICLE PUBLICATION DATE
17-May-2023
High-quality satellite imagery swiftly reveals post-earthquake details
IMAGE: THE DATA USED FOR THE INTERPRETATION OF THE SEISMIC ZONE AND THE DISTRIBUTION OF THE INTERPRETED RUPTURE ZONES. view more
CREDIT: THE AUTHORS
Remote sensing imagery is widely used in disaster response due to its easy accessibility and timeliness and can clearly reflect changes in features caused by earthquakes using pre- and post-earthquake image comparisons.
The Mw 7.8 and Mw 7.5 earthquakes that occurred in Turkey on 6 February 2023 caused severe loss of life and destruction of roads and buildings. This event was the biggest earthquake to strike the Eastern Anatolian Fault Zones (EAFZ) since the 1990s. To gain a timely and in-depth insight into the earthquakes, a team of researchers from the Institute of Earthquake Forecasting in Beijing, China, used high-resolution Maxar and GF-2 satellite data to obtain spatial interpretations of part of the rupture zone in the epicenter of this earthquake, as well as seismic landslides and soil liquefaction developed around the rupture zone.
“We searched for feature dislocations and measuring the amount of dislocations, which provided a timely and comprehensive understanding of the earthquake damage caused by this earthquake,” shared Yueren Xu, corresponding author of the study.
The team initially interpreted a rupture zone of approximately 75 km in length and found that the surface showed a gradual widening of the spreading width and a gradual decrease in the amount of horizontal dislocations to immeasurable levels.
“Secondary hazards such as liquefaction are mainly found in rivers or low-lying terrain at the end of the rupture zone, and landslides are found in valley areas near the rupture zone,” said Xu.
The findings are published in the KeAi journal Earthquake Research Advances.
The researchers proposed that earthquakes in Turkey will not have a direct response on significant magnitude seismic activity in western China. This is due to the continental collision involving various plates across plus their contrastive seismically active zones throughout the world.
“Despite both China and Turkey being part of the same Eurasian seismic region, they variably exhibit tectonic mechanism dissimilarities,” added Xu.
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Contact the author: Xu Yueren, Key Laboratory of Earthquake Prediction, Institute of Earthquake Forecasting, China Earthquake Administration, xuyr@ief.ac.cn.
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 100 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
JOURNAL
Earthquake Research Advances
METHOD OF RESEARCH
Case study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Preliminary report of coseismic surface rupture (part) of Turkey's Mw7.8 earthquake by remote sensing interpretation
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