Core Samples from Nepal’s Lake Reveal Random Patterns of Historical Earthquakes
Zakaria Ghazoui-Schaus, BAS
While some experts argue that northern India and western Nepal are overdue for significant earthquakes, recent studies indicate this notion may be a myth. Historical data reveals small earthquakes have occurred randomly in the region for thousands of years.
Frequently, officials and media label densely populated fault-adjacent areas, such as Istanbul, Seattle, and Tokyo, as being “overdue” for a major earthquake. The last significant earthquake on the central Himalayan fault segment in India and Nepal was recorded in 1505. Some researchers suggest that earthquakes in the area occur approximately every 500 years, indicating that a major quake could be on the horizon, as highlighted in a study.
However, new findings reveal at least 50 earthquakes of magnitude 6.5 or higher have transpired in this region over the past 6,000 years, including 8 since 1505, according to this research. Notably, these earthquakes did not exhibit regular patterns, occurring randomly instead.
“It is essential to shift our focus from debating the periodicity of earthquakes in the Himalayas to acknowledging that they occur randomly, and assess the risks accordingly,” emphasizes Zakaria Ghazoui-Schaus of the British Antarctic Survey, who participated in the research.
The relentless collision of the Indian and Eurasian tectonic plates forming the Himalayas contributes to one of Earth’s largest seismic zones. This extensive 2,400-kilometer fault has generated powerful earthquakes, including the catastrophic 7.8 magnitude earthquake in 2015 that tragically claimed nearly 9,000 lives in and around Kathmandu.
Despite this, limited evidence of seismic activity has been found in the central fault section just west of Kathmandu, sparking concerns that pressure in this “seismic gap” could lead to a devastating magnitude 8 or 9 earthquake.
Ghazoui-Schaus suggests that this perception stems from a “knowledge gap” rather than tectonic inactivity. Traditional methods for locating earthquake evidence in the Himalayas often involve digging trenches to find surface cracks, which might detect major quakes but overlook smaller “shadow earthquakes” that did not cause surface damage.
Former British Geological Survey seismologist Roger Masson states, “Traditional paleoseismology only yields sparse records of the largest earthquakes, while historical catalogs generally suffice for earthquakes up to magnitude 4.” This bias leads to inflated estimates of long “occurrence intervals,” or “recurrence periods,” which represent the average time between earthquakes of a certain magnitude in an area.
To enhance the seismic record of the central Himalayas, Ghazoui-Schaus and his team visited Rara Lake in western Nepal in 2013, collecting a 4-meter sediment core using a rubber boat.
Research Team Prepares Equipment for Sediment Core Sampling at Rara Lake in Nepal
Zakaria Ghazoui-Schaus, BAS
The researchers analyzed sediment cores containing turbidites—layers that finely layer sediment on coarser sediments deposited on the lake bed by underwater landslides caused by earthquakes. Their analysis identified 50 earthquakes of magnitude 6.5 or greater over the past 6,000 years, each dated according to its core depth, likely releasing energy that alleviated fault tension, says Ghazoui-Schaus.
Statistical evaluations indicated that while earthquakes often occur in swarms, these swarms are random. This finding aligns with seismologists’ expectations based on contemporary records, marking one of the first confirmations through paleoseismological evidence.
If I were constructing a house in western Nepal, I would certainly prioritize building it more robustly,” notes Ghazoui-Schaus. Masson adds that despite the random occurrence of earthquakes, calculating the average interval between them remains valuable for anticipating seismic activity that could threaten vulnerable structures like bridges and dams.
“When planning for the next century, it’s crucial to estimate how many earthquakes of specific magnitudes may occur. Being prepared ensures we can withstand quakes whenever they strike, regardless of whether it’s next year or a decade from now,” he states succinctly.
Unusual marks found on rocky surfaces in Italy may have been created by a group of sea turtles reacting to an earthquake around 83 million years ago.
Extreme climbers stumbled upon a peculiar feature in a restricted area on the slopes of Monte Conero along Italy’s east coastline.
Over 1,000 prints are evident in two distinct spots. One location is situated over 100 meters above sea level, while the other is a ledge that collapsed onto La Vera Beach. These limestone rocks were formed from fine sediments that settled on the shallow ocean floor during the Cretaceous era.
The climbers captured photographs that were subsequently shared with the Alessandro Montanari Cordigioco Geological Observatory in Italy and colleagues. Scientists were then granted permission by the Conero Regional Park authority to explore the area both on foot and using drones.
Montanari mentioned that while it is challenging to identify which animal made the marks, the only two types of vertebrates inhabiting the ocean then were fish and marine reptiles. The researchers dismissed fish, plesiosaurs, and mosasaurs, leading to the conclusion that sea turtles are the most probable culprits.
Given the dynamic nature of the ocean floor, the prints must have been buried almost immediately after formation to remain intact, potentially occurring during an earthquake.
“[It may have been] the powerful earthquake that frightened the poor animals, which were peacefully residing in their nutrient-rich shallow-water habitat,” states Montanari.
“In panic, they swam towards the open sea on the west side of the reef, leaving paddle impressions on the soft seabed.”
However, the notion of a turtle swarm remains speculative, and the team is eager to collaborate with ichthyologists who specialize in analyzing fossilized tracks for the next phase of their research.
Anthony Romilio, a researcher from the University of Queensland in Australia, claims that if these marks indeed are from sea turtles, they would be “potentially the most numerous in the world.”
Nevertheless, he has yet to visit the site or view high-resolution images and doubts the prints belong to sea turtles. “The surface patterns do not exhibit the spacing, rhythm, or anatomy expected in a sea turtle’s flipper stroke,” he comments. “I suspect they are abiotic formations rather than biological in origin.”
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Aerial overview of Nabuyatom Crater, located south of Lake Turkana, Kenya
Martin Harvey/Alamy
The arid conditions of East Africa have led to a decline in the water levels of Kenya’s Lake Turkana for millennia, triggering rising earthquakes and volcanoes beneath its surface. This risk associated with climate change could potentially impact other water bodies globally as precipitation and drought patterns shift.
Lake Turkana is often referred to as the cradle of humanity. Fossils from at least six different human species, dating back 4.2 million years, have been unearthed here, with some believed to have lived alongside each other. As the size of these lakes decreased over thousands of years, our ancestors faced not just a more arid environment but also increased geological activity.
“We believe that during these eras, there would have been a rise in the frequency of earthquakes and volcanic eruptions,” states Christopher Scholz, a researcher at Syracuse University in New York. “The challenging conditions observable today in the region would have been further intensified.”
Situated in the Great Rift Valley between Kenya and Ethiopia, Lake Turkana is the world’s largest desert lake, a greenish body of saline water surrounded by sandy shrublands and breezy outcrops. However, 9,000 years ago, it was considerably larger and enveloped by rich grasslands and forests.
Between 4,000 and 6,000 years ago, the climate shifted towards drier conditions, causing the lake’s level to fall by 100 to 150 meters. Such a drop in water levels lessens the pressure on the lakebed below, potentially influencing seismic behavior. To investigate the impact of this climatic alteration, Scholz and his team pinpointed specific sediment layers that correspond to various historical periods from cores previously extracted from the lakebed.
They conducted sonar scans from a boat over 27 faults on the lake floor to analyze how the sediment layers were displaced vertically on either side of each fault. Their findings suggested that as the climate grows drier, the sides of faults slip past one another at an accelerated average rate of 0.17 millimeters per year.
“The key mechanism here involves tightening and loosening this deformation area, which causes earthquakes,” Scholz explains. “A drier climate coupled with lower lake loads will facilitate a slicker fault line.”
Computer simulations indicate that as water mass diminishes, an increase in magma movement occurs beneath the lake. One of the volcanic islands in Lake Turkana erupted in 1888.
Research previously demonstrated that declining sea levels heighten volcanic activity at ocean ridges. However, this provides the first solid evidence of a similar trend occurring around this lake, according to Ken McDonald from the University of California, Santa Barbara. “It’s akin to loosening the cork on a champagne bottle,” he remarks. “Reducing the pressure increases the likelihood of magma ascending within the Earth’s crust and erupting.”
While climate change is currently leading to higher water levels in Lake Turkana, it may take millennia for seismic and volcanic activities to stabilize significantly.
Nevertheless, the authors of the study advocate that seismic risk assessments should take into account how climate change affects water levels. Moreover, policymakers should factor in seismic vulnerabilities when planning the construction or deconstruction of dams.
“They should install [seismometers] before making any substantial alterations,” McDonald advises.
Recent research suggests that the concealed structural weaknesses in the Yukon, Canada, may be primed to trigger a significant earthquake of at least magnitude 7.5, as outlined in the latest study.
The Tintina Fault, stretching from northeastern British Columbia to central Alaska, has been silently accumulating tension for over 12,000 years. A new investigation previously deemed relatively harmless indicates that it remains very active.
Regrettably, scientists are unable to predict when the next major quake will strike.
“Our findings indicate that the fault is active and continues to build strain,” said Dr. Theron Finley, the lead author of the study published in Geophysical Research Letters, in a statement to BBC Science Focus. “I expect it will eventually rupture again.”
The Tintina Fault is classified as a “right-lateral strike-slip fault,” where two blocks of the Earth’s crust slide horizontally past each other. If one side moves to the right during an earthquake, it’s identified as right-lateral.
Over the ages, one side of the fault has shifted approximately 430 km (270 mi), during a geological period that spanned roughly 560 to 33.9 million years ago, predominantly in the Eocene epoch.
The Tintina Fault extends 1,000 km (600 mi) from northeastern British Columbia to Alaska. – Credit: National Park Bureau
While minor earthquakes occasionally occur in the region, the Tintina Fault has generally been considered dormant.
“There have been small earthquakes in the 3-4 magnitude range detected along or near the Tintina Fault,” Finley noted. “However, nothing has strongly indicated that a larger outbreak is likely.”
This perspective changed when Finley and his team revisited the fault with advanced technology. By integrating satellite surface models with drone-mounted Light Detection and Ranging (LiDAR) data, researchers uncovered hidden seismic activity within the dense Yukon forests.
The landscape revealed cliffs associated with the fault, forming long, narrow terrains created when a quake pushed material to the surface, often collapsing in the process. These features can span dozens or even hundreds of kilometers, but are typically only a few meters tall and wide.
“In the case of the Tintina fault, these features appear as a series of intriguing mounds,” Finley stated.
By dating these surface formations, researchers determined that the fault has ruptured multiple times over the last 2.6 million years, though no significant earthquakes have occurred in the past 12,000 years.
Fortunately, the region is sparsely populated. However, if the fault does rupture, Finley cautioned that major landslides, infrastructure damage, and impacts on nearby communities would be highly probable.
“We want to emphasize that we don’t have a precise sense of how imminent an earthquake is,” he noted. “Our observations indicate it has been a long time since the last significant quake, but there’s no way to know if one is more likely in the near or distant future.”
Finley remarks that the fault has been confirmed as active, and the next step is to better estimate the frequency of large earthquakes in the area. This could help provide a more reliable timeline, even though scientists cannot accurately forecast when the next rupture may happen. Stay tuned.
“Earthquakes don’t necessarily occur on a regular basis, but they can give us a clearer understanding of how often we can expect significant events,” Finley explained. “Regardless, when the Tintina fault finally releases, it won’t be inconsequential.”
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About our experts
Theron Finley is a geologist at the Yukon Geological Survey. He recently obtained a doctorate from the University of Victoria in Canada and has conducted research on active faults in Western Canada, utilizing remote sensing, structural geology, and paleoseismology.
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Microorganisms may derive energy from surprisingly confined environments
Book Worms / Public Domain Sources from Aramie / Access Rights
Fractured rocks from earthquakes could reveal a variety of chemical energy sources for the microorganisms thriving deep beneath the surface, and similar mechanisms may feed microorganisms on other planets.
“This opens up an entirely new metabolic possibility,” says Kurt Konhauser, from the University of Alberta, Canada.
All life forms on Earth rely on flowing electrons to sustain themselves. On the planet’s surface, plants harness sunlight to create carbon-based sugars that are consumed by animals, including humans. This initiates a flow of electrons from the carbon to the oxygen we breathe. The chemical gradient formed by these carbon electron donors and oxygen electron acceptors, known as redox pairs, generates energy.
Underground, microbes also depend on redox pairs, but these deep ecosystems lack access to various solar energy forms. Hence, traditional carbon-oxygen pairings are inadequate. “Challenges remain in identifying these underground [chemical gradients]. Where do they originate?” Konhauser questions.
Hydrogen gas, generated by the interaction of water and rock, serves as a primary electron source for these microbes, much like carbon sugars do on the surface. This hydrogen arises from the breakdown of water molecules, which can occur when radioactive rocks react with water or iron-rich formations. During earthquakes, when silicate rocks are fragmented, they expose reactive surfaces that can split water, producing considerable amounts of hydrogen.
However, to utilize that hydrogen, microorganisms require electron acceptors to complete the redox pair. Attributing value solely to hydrogen is misleading. “Having the food is great, but without a fork, you can’t eat it,” remarks Barbara Sherwood Lollar from the University of Toronto, Canada.
Konhauser, Sherwood Lollar, and their research team employed rock-crushing machines to simulate the reactions that yield hydrogen gas within geological settings, which could subsequently form a complete redox pair. They crushed quartz crystals, mimicking strains in various types of faults and mixing the water present in most rocks with different iron and rock forms.
The crushed quartz reacted with water to generate significant quantities of hydrogen, both in stable molecular forms and more reactive species. The team’s findings revealed many of these hydrogen radicals react with iron-rich liquids, creating numerous compounds capable of either donating or accepting enough electrons to establish different redox pairs.
“Numerous rocks can be harnessed for energy,” Konhauser pointed out. “These reactions mediate diverse chemical processes, suggesting various microorganisms can thrive.” Secondary reactions involving nitrogen or sulfur could yield even broader energy sources.
“I was astonished by the quantities,” said Magdalena Osburn from Northwestern University, Illinois. “It produces immense quantities of hydrogen, and it also initiates fascinating auxiliary chemistry.”
Researchers estimate that earthquakes generate far less hydrogen than other water-rock interactions within the Earth’s crust. However, their insights imply that active faults may serve as local hotspots for microbial diversity and activity, Sherwood Lollar explained.
Importantly, a complete earthquake isn’t a prerequisite. Similar reactions can take place as rocks fracture in seismically stable areas, like continents or geologically dead planets such as Mars. “Even within these massive rocks, you can observe pressure redistributions and shifts,” she noted.
“It’s truly exciting to explore sources I was recently unfamiliar with,” stated Karen Lloyd from the University of Southern California. The variety of usable chemicals produced in actual fault lines is likely even more diverse. “This likely occurs under varying pressures, temperatures, and across vast spatial scales, involving a broader range of minerals,” she said.
Energy from infrequent events like earthquakes may also illuminate the lifestyles of what Lloyd refers to as aeonophiles—deep subterranean microorganisms thought to have existed for extensive time periods. “If we can endure 10,000 years, we may experience a magnitude 9 earthquake that yields a tremendous energy surge,” Lloyd added.
This research is part of a growing trend over the last two decades that broadens our understanding of where and how organisms can endure underground, states Sherwood Lollar. “The deep rocks of continents have revealed much about the habitability of our planet,” she concluded.
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A report published on Tuesday by German multinationals revealed that weather-related disasters in the first half of this year caused $93 billion in damages within the United States.insurancecompany.
An analysis from Munich RE, the largest reinsurer in the world, indicated that over 70% of the global damages from this year’s weather disasters occurred in the United States, leading to a burden of $22 billion on uninsured Americans and their local governments.
The report underscores the increasing economic impact of wildfires, severe storms, and other extreme weather events both in the US and globally. It also highlights the escalating insurance crisis in nations frequently afflicted by such disasters.
“Approximately 90% of all industry losses were observed, with $72 billion out of $80 billion occurring in the US,” stated Tobias Grimm, chief climate scientist at Munich RE. “That is remarkable.”
The catastrophic wildfires in Southern California in January ranked as the most expensive disaster in the country during the first half of 2025. The two major fires, responsible for at least 30 fatalities and displacing thousands, swept through the Pacific Ocean’s Pallisad and Altadena neighborhoods.
Munich RE estimated the wildfire losses at $53 billion, including costs affecting uninsured residents. The reinsurer noted that these flames in the Los Angeles area resulted in “the highest wildfire loss ever recorded.”
The significant economic and social impacts of wildfires can be partly attributed to the increasing development in fire-prone areas.
“In many instances, losses are growing due to property developments causing damage,” Grimm explained. “People continue to reside in high-risk zones.”
Urbanization in disaster-prone areas can similarly escalate the costs associated with other weather-related events, like hurricanes and floods, which are becoming more frequent and severe due to climate change.
Research indicates that climate change is becoming increasingly frequent as temperatures rise and drought conditions worsen. Consequently, the intensity of wildfires is also increasing.
A report by the World Weather Attributes Group issued in late January found that high temperatures, along with dry and windy conditions conducive to fire spread in Southern California, could be approximately 35% more likely due to human-induced global warming.
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Advanced warnings can save lives before an earthquake, such as the 5.6 magnitude tremor that affected hundreds of people in Indonesia in 2022
Aditya Aji/AFP via Getty Images
Your mobile device might already be part of the billions of gadgets worldwide functioning as an early warning system for earthquakes across numerous nations.
Launched in 2020, Google’s Android Earthquake Alerts System has expanded to reach 2.3 billion Android phone and smartwatch users, enabling them to receive alerts about seismic activity, according to a recent study by Google researchers. However, these devices do more than just issue warnings; they also contribute to earthquake detection.
“Billions of Android devices come together to form mini-seismometers, establishing the world’s largest earthquake detection network,” states Richard Allen, a visiting researcher at the University of California, Berkeley.
Developed by Allen and his team, the system analyzes vibrations captured by accelerometers in Android devices and smartwatches. This collective network of sensors can determine the magnitude of an earthquake and identify which users are in close range of danger for timely warning messages.
Google’s system alerts users when it detects tremors of 4.5 or greater on the Richter scale. Yet, Allen notes that the system “may not detect all earthquakes” due to the need for sufficient nearby devices. For instance, earthquakes from most central ridges may go undetected, but the system can identify seismic events occurring up to hundreds of kilometers offshore.
A critical challenge is the swift and accurate assessment of each earthquake’s magnitude. Researchers have refined the detection algorithm over time by creating regional models that better represent local structural movements and by considering the varying sensitivities of different Android devices.
According to Allen, Google’s global system is now as effective as the ShakeAlert system, which serves the US West Coast, as well as Japan’s early warning system. He emphasizes that Google’s initiative is intended to complement, not replace, seismometer-based services, which provide warnings like ShakeAlert to West Coast residents. “Many earthquake-prone areas lack the local seismic network necessary for timely alerts,” Allen comments.
Google’s system serves as a “unique source” for nations without an existing earthquake early warning framework, states Katsu Goda from Western University in Canada, who is not affiliated with the project. He noted that even in regions with existing alert systems, Google’s solution reaches a broader audience.
The system currently delivers alerts to 98 countries and territories, including the United States, but excluding the UK. “Our focus has primarily been on countries at high historical risk for earthquakes that lack existing early warning solutions,” explains Marc Stogaitis from Google.
Android devices in the region captured seismic waves during the 6.2 magnitude earthquake in Turkey in April 2025
Data SIO, NOAA, US NAVY, NGA, GEBCO, LDEO-COLUMBIA, NSF, Landsat/Copernicus, Google Earth
A recent study evaluating system performance and accuracy revealed that the system generated alerts for 1,279 earthquake events up until March 2024, with only three false alarms. Of these, two were due to thunderstorms and one stemmed from an unrelated mass notification that caused several phones to vibrate. The research team improved their detection algorithm to minimize these types of false alerts.
Most Android devices are automatically enrolled in a mobile phone-based seismometer network and receive alerts regarding nearby earthquakes by default, although users can modify these settings. In a Google User Survey, over one-third of participants reported receiving alerts before feeling any shaking, and most indicated that these notifications were extremely beneficial.
If users remain subscribed to alerts, they will receive two types of notifications: more urgent action alerts encouraging immediate precautions like “drop, cover, hold,” which often provide only a few seconds of advance warning, and out-of-interference alerts that share general information, allowing a brief window before a user experiences the earthquake.
“The nature of earthquakes implies that there are less warning time before strong shaking compared to weaker events,” states Stogaitis. “Nonetheless, we are continuously examining adjustments to our alert strategies to extend warning times for future earthquakes.”
As an earthquake ruptures along the Cascadia subduction zone fault, much of the US West Coast will experience intense shaking for five minutes, with tsunamis potentially generating waves up to 100 feet crashing towards the shore. However, this is only the onset of anticipated devastation.
Even if coastal communities in Northern California, Oregon, and Washington withstand the initial earthquake, recent research indicates that flooding could inundate many of these susceptible regions. This is due to an expected drop of 6½ feet in the entire coastal land when the earthquake strikes, according to a new study published Monday in the Proceedings of the National Academy of Sciences (PNA).
Researchers examined earthquake and flood models to provide some of the most comprehensive predictions about how Cascadia earthquakes can lower or subside coastal land, potentially affecting over twice as many people, structures, and roadways as currently established. The exacerbating effects of climate change are projected to raise sea levels, compounding the issue over time.
“The repercussions of these hazards will linger for decades or even centuries following the earthquake,” stated Tina Dura, the study’s lead author. “Tsunamis will strike and have a considerable impact. Don’t misunderstand me; however, a lasting change in flood frequency… that is a critical concern.”
The team will operate the Vibracore Rig in Silets Bay, Oregon, collecting deep sediment cores in 2022 for tsunami deposits and paleoseismic analysis. Tina Dura
Dura explained that geological fossil evidence suggests that previous Cascadia earthquakes resulted in a significant drop in land level, transforming once dry areas into tidal mud flats along the Pacific Northwest’s estuaries.
An assistant professor of geoscience at Virginia Tech, Dura noted: “This is how we have a harbor…and where we’ve established towns, yet that land will plummet by a maximum of two meters.”
The Cascadia subduction zone fault offshore of North America presents an imminent threat, capable of generating magnitude 9.0 earthquakes. Such events are expected to occur on average every 450-500 years, with the last major quake dating back to 1700.
The national seismic hazard model indicates a 15% chance of an earthquake measuring 8.0 or higher occurring along the zone within the next 50 years.
When the fault ruptures, experts assert that it could lead to the most catastrophic natural disaster in the nation’s history. Simulations from 2022 predict that the Cascadia earthquake could damage around 620,000 buildings in the Pacific Northwest, including 100 hospitals and 2,000 schools, resulting in over 100,000 injuries and approximately 14,000 fatalities.
Recent findings emphasize that coastal planners must seriously consider not only the immediate threats of strong shaking and tsunami waves but also the long-term impacts of land reshaping and rapid subsidence of the coastline itself.
“There will be the flooding itself, as well as enduring changes in land elevation along the coast, greatly affecting community planning,” remarked Harold Tobin, director of the Pacific Coast Earthquake Network and professor at the University of Washington. “Where will schools and hospitals be built? Where will transportation networks be established? A long-term perspective is vital.”
Following the earthquake, Dura’s research predicts that towns along the Pacific Northwest coastline, such as Seaside, Oregon, Westport, Washington, and Aberdeen, Washington, will likely experience frequent flooding, at least once every century.
The study also highlights that climate change-induced sea level rise will accelerate, aggravating the consequences of post-earthquake flooding in the future.
A field team across the mouth of the Salmon River in Oregon will transport coring and surveying equipment to the next sampling site in 2023. Mike Pridy
Global average sea levels have risen by approximately 8-9 inches since 1880, according to the National Oceanic and Atmospheric Administration (NOAA). Dramatic acceleration in sea level rise is anticipated in the coming decades due to global warming, with NOAA estimating an increase of 10-12 inches.
The impact of sea level rise varies depending on location and can significantly affect the coastline.
In places like Chesapeake Bay, Virginia, land is gradually sinking, a process termed subsidence, while portions of the Pacific Northwest are experiencing uplift due to continental movements. This uplift can offset some of the sea level rise.
The uplift is attributed to the stress build-up within the plates forming the Cascadia subduction zone. In this zone, the Juan de Fuca plate is forced beneath the North American plates, causing a slight upward movement of land.
Currently, the subduction zone faults remain inactive, accumulating stress. When the fault eventually ruptures, the released plate bow leads to rapid land-level subsidence, effectively negating the uplift for centuries.
“It all transpires in a matter of minutes, resulting in meter-level drops,” stated Dura. “The land continues to shift, and as I mentioned, this has ramifications that will last for decades and centuries. Consequently, the critical areas of the floodplain are significantly impacted.”
Separated by more than 600 miles of land, the epicenter of Friday’s earthquake in Myanmar was far from the skyscrapers of Bangkok. The collapse of a 33-storey building under construction raises questions about how the shaking in Bangkok, the capital of Thailand, compares to past earthquakes.
One of the answers lies in low-frequency seismic waves that can travel long distances and impact high-rise buildings.
During a significant earthquake event, different frequencies of shaking are emitted simultaneously. Some produce rapid vibrations, while others generate low-frequency shaking.
This was evident during the Myanmar earthquake when violent, high-frequency seismic waves caused destruction near the epicenter, taking down low-rise buildings and structures made of brittle materials.
High-frequency seismic waves released during an earthquake dissipate within the Earth, while low-frequency waves can travel further along the Earth’s crust.
Low-frequency waves were observed during the 2002 Denali earthquake in Alaska, causing vibrations as far as Texas and Louisiana.
These seismic waves resonate with tall buildings, affecting them differently based on their design and height.
Similar to tuning forks producing varied sounds, buildings react uniquely to earthquakes depending on their characteristics.
Low-frequency seismic waves played a crucial role in the 1985 earthquake that caused extensive damage in Mexico City.
Seismic waves resonated through the soft soils of the Chao Phraya River Delta in Bangkok during the recent earthquake event.
Engineers have realized the underestimated risks posed by soft soils amplifying earthquake effects in recent years.
Cities like Bangkok, Mexico City, Los Angeles, and others are subject to basin effects, increasing earthquake forces, especially at low frequencies.
In 1985, the frequency of seismic waves was critical in understanding earthquake damage in Mexico City, particularly affecting buildings between 7-18 stories tall.
Old low-rise masonry buildings performed better during earthquakes in comparison to taller structures, highlighting vulnerability despite seeming stability.
Engineers shifted to building more flexible skyscrapers in earthquake-prone regions starting from the 1950s.
Concerns persist about the vulnerability of tall buildings to less frequent but more destructive earthquakes.
The fault destruction under modern cities during a major earthquake event can have devastating effects on tall buildings, despite engineering precautions.
Dr. Heaton warns about the rapid and violent movement caused by fault slip during earthquakes, potentially leaving tall buildings unsupported.
Buildings’ bases in earthquake-prone regions must be engineered to withstand such movements to prevent catastrophic collapses.
A replica of the “Welcome Stranger,” a 100 kg gold nugget discovered in Australia in 1869.
Ian Dagnall/Alamy
Earthquakes can create electric fields that attract gold dissolved in liquids pushed up from deep within the earth, causing gold nuggets to form in the quartz.
Giant gold nuggets are often associated with quartz, a ubiquitous but chemically inert mineral. The world's largest gold nuggets can weigh nearly 100 kilograms, but until now no one has been able to explain how such masses of precious metal formed.
“The mystery was how someone could create such a large nugget of gold in one place without any obvious chemical or physical traps,” he said. Chris Voysey At Monash University, Melbourne.
Voysey and his colleagues discovered a possible mechanism: applying pressure to the quartz creates a voltage that attracts gold dissolved in water.
The secret lies in the structure of quartz, Voysey explains. Quartz is the only abundant mineral whose crystals have no center of symmetry. This means that when these crystals are strained or stressed by seismic activity, their internal electromagnetic makeup changes, generating electricity. Electricity generated in response to mechanical stress is known as piezoelectricity.
Gold-bearing hydrothermal fluids rise up through fissures during seismic activity from the mid-to-lower crust, 15-20 km below the surface, but gold is so dilute that it would take the equivalent of five Olympic swimming pools of hydrothermal fluid to produce 10 kg of gold.
Voysey and his colleagues hypothesized that the piezoelectric properties of quartz would cause the gold to concentrate in nodules within the veins during repeated earthquakes. To test this idea, the team performed experiments in which they placed quartz crystals in a gold-containing solution and applied moderate pressure from an actuator.
Quartz samples that were not subjected to pressure did not attract gold, but samples subjected to force generated a voltage and attracted the metal. Some of the samples were coated with iridium to accentuate the piezoelectric response of the quartz and artificially mimic the expansion of seismic activity. In these samples, large gold flakes grew, over 6000 nanometers, compared to 200-300 nanometers in uncoated quartz.
Once gold starts to deposit on the quartz, it quickly attracts other gold, Voysey says. “Gold is a conductor, so gold in solution tends to deposit on top of existing gold,” he says. “It becomes like a lightning rod that attracts more gold.”
Earth can be visualized as a chaotic mass of rocky tectonic plates floating on a sea of molten metal. These plates are constantly moving and rubbing against each other, releasing massive amounts of energy that result in earthquakes. So, what is the largest earthquake ever recorded?
It is estimated that around 20,000 earthquakes occur worldwide each year, averaging about 55 earthquakes per day. Of these, approximately 16 are categorized as major (magnitude 7 or higher) annually.
Most earthquakes take place under the sea, posing a significant threat due to the potential of triggering massive tsunamis upon hitting the land after an undersea earthquake.
The Richter scale was introduced in the 1930s to standardize earthquake magnitude measurements, making it easier to compare sizes. However, the scale had its limitations. Since then, the moment magnitude (Mw) scale has been used to rank the top 10 earthquakes.
Similar to the Richter scale, the moment magnitude scale is logarithmic, meaning that with each integer increase on the scale, the earthquake becomes 10 times more powerful. For instance, a 9 Mw earthquake is 6 magnitude levels stronger than a 1,000Mw earthquake.
Here are the top 10 largest earthquakes ever recorded:
10 – Indian Ocean, 2012
A security guard walks through damaged buildings the day after a major earthquake struck the west coast of Banda Aceh, Indonesia, on April 11, 2012. A tsunami watch for the Indian Ocean was lifted hours after two major earthquakes struck off the coast of Indonesia's Sumatra island. People run away from the coast in fear. Image credit: Adek Berry/AFP/Getty Images
The Aceh province of Indonesia, known for seismic activity, experienced a massive 8.6 Mw earthquake on April 11, 2012. The earthquake, which occurred 610km off the coast of Banda Aceh, was followed quickly by an 8.2 Mw earthquake. While the earthquakes caused mass panic and coastal evacuations, physical damage was minimal, and the feared tsunami did not materialize.
This seismic event was the largest instance of a sideslip earthquake in recorded history, characterized by horizontal movement of the crust along two plates rather than vertical motion. Such earthquakes are less likely to trigger significant tsunamis compared to vertical strike-slip faults.
9 – Aleutian Islands, USA, 1946
Main Street in Hilo, Hawaii, USA, is damaged beyond recognition after a tidal surge on April 1, 1946. Image courtesy of Getty
In the North Pacific Ocean, the Aleutian Islands experienced an 8.6 Mw earthquake in April 1946, triggering a widespread tsunami that caused extensive damage. This tsunami, traveling at 800km/h, reached the Hawaiian Islands in just five hours, resulting in 159 deaths and significant destruction.
Due to the earthquake’s magnitude and location, the wave height on Unimak Island, near the epicenter, reached 42 meters. The earthquake also generated a tsunami in Antarctica, over 15,500 km away.
8 – Assam, India, 1950
A damaged bridge can be seen in this image. Photographed on August 25, 1950 in Assam, India, shortly after the earthquake. Image credit: Keystone-France/Gamma-Rapho/Getty Images
The most powerful earthquake ever recorded on land struck between India’s Assam state and Tibet in 1950. This earthquake, measuring 8.6 Mw, resulted from the collision of the Indian and Eurasian tectonic plates.
The earthquake triggered massive landslides in Tibet, causing entire villages to slide into the river and be swept away. In India, 70 villages were destroyed due to landslides and natural dam collapses, resulting in an estimated 4,800 fatalities.
The tragedy claimed around 1,500 lives in India and 3,300 in Tibet.
7 – Mouse Island, USA, 1965
Black volcanic sand on Kiska Island, part of the Rat Islands, Alaska, USA. Image credit: Alamy
The Rat Islands, part of the volcanic Aleutian Islands chain, experienced an earthquake in 1965 that triggered a tsunami over 10 meters high on Siemia Island, 304 kilometers away. Remarkably, the resulting tsunami still reached Hawaii, 4,200 km away, generating 1-meter waves despite its remote epicenter.
Fortunately, the damages and casualties were limited due to the sparse population in the affected areas.
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6 – Chile, 2010
Soldiers stand guard as firefighters put out a fire at a supermarket in Concepción, Chile, on March 1, 2010, three days after the devastating earthquake that rocked the country. Image credit: Claudio Santana/AFP/Getty Images
On February 27, 2010, a powerful 8.8 Mw earthquake struck the coast of central Chile, near Concepción. Lasting around three minutes, the quake’s impact was felt as far as Sao Paulo, Brazil, 4,620 kilometers away.
The city of Concepción, known for its earthquake history, endured severe damage. In 1939, 1953, and 1960, previous earthquakes caused significant destruction and loss of lives. The 2010 earthquake resulted in tsunami warnings being issued to 53 countries due to its large magnitude and ocean floor rupture.
5 – Severoklisk, Russia, 1952
The site of the town of Severo Kurilsk before it was destroyed by the tsunami in 1952. The site of the modern town, rebuilt at a higher level, is not visible in this 2006 image. Image credit: Victor Morozov/Wikipedia
In 1952, Severokilsk, a volcanic archipelago in Russia’s Kuril Islands located 1,300 km northeast of Japan, experienced a massive earthquake. This earthquake triggered an 18-meter high tsunami that devastated the region, claiming nearly half of the small town’s population.
Residents, forewarned by the earthquake, sought safety on higher ground but returned after the initial wave passed. Tragically, a second wave struck as people returned home, resulting in numerous casualties.
The town was subsequently rebuilt on higher ground following the catastrophe. To date, this remains the largest earthquake documented in Russia.
4 – Tohoku, Japan, 2011
This photo taken on March 11, 2011 shows a tsunami hitting the coast of Minamisoma City, Fukushima Prefecture. Image credit: Teiji Tomizawa/Jiji Press/AFP/Getty Images
On March 11, 2011, Japan witnessed the largest earthquake ever recorded in the country near Tohoku. The earthquake, with a magnitude of 9.0, had its epicenter about 72 kilometers off the northeast coast of Honshu, resulting in significant movement of the Earth’s axis and land shift.
The ensuing tsunami, a devastating consequence of the earthquake, swept away entire communities and breached previously established defenses. Tsunami waves exceeding 40 meters hit certain coastal areas, overwhelming earlier sea wall predictions.
Additionally, the earthquake triggered a nuclear disaster at the Fukushima Daiichi Nuclear Power Plant due to infrastructure damages caused by the tsunami. The resulting meltdown led to the release of nuclear material into the atmosphere.
The earthquake claimed over 22,000 lives, underscoring its catastrophic impact.
3 – Sumatra, Indonesia, 2004
The overview shows how Meurabo, Indonesia was submerged under water on December 28, 2004, after an earthquake and tidal wave hit Aceh province on December 26, 2004. Image credit: HO/AFP/Getty Images
An enormous 9.1 Mw earthquake, affecting a 1,300km stretch of the Sumatra trench, rocked the region on December 26, 2004. This subduction earthquake occurred over centuries as the Burmese microplate slid under the Indian plate, unleashing massive destruction and spawning a devastating tsunami.
Rising more than 20 meters, the ocean floor shift generated a tsunami exceeding 30 meters in height. The deadly waves swept through coastal areas in 14 nations, resulting in an estimated 228,000 fatalities, with Indonesia, Sri Lanka, India, and Thailand bearing the brunt of the disaster.
This is the most potent earthquake ever documented in Asia and a defining natural calamity of the 21st century.
2 – Alaska, USA, 1964
Earthquake damage on 4th Avenue in Anchorage, Alaska, USA on March 27, 1964. Image courtesy: UPI/Getty Images
Alaska, USA, experienced a powerful earthquake in 1964, rupturing 1,000 km of the Pacific and North American plates at once. Lasting nearly five minutes, the earthquake impacted vast areas of North America, with Anchorage suffering severe damage due to inadequate earthquake-proof structures and infrastructure.
The earthquake, the second-strongest recorded in history, significantly influenced North American geology.
1 – Valdivia, Chile, 1960
The remains of Valdivia after a devastating earthquake struck the city on May 22, 1960. The earthquake caused high waves and a volcanic eruption. Image credit: Alamy
In 1960, the most massive earthquake on record struck near Valdivia, Chile, with a magnitude of 9.5. This event, one of the deadliest earthquakes in history, resulted in around 5,700 deaths.
Occurring around 3:00 PM local time, the earthquake lasted approximately 10 minutes, causing considerable land subsidence along Chile’s coast, landslides, and road blockages.
Moreover, the tsunami triggered by the earthquake caused extensive coastal devastation.
Chileans had been forewarned by a series of powerful foreshocks, enabling them to prepare for the impending disaster, likely contributing to the relatively fewer casualties.
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