New model for the complex earthquake patterns of the Phlegraean Fields near Naples

Combining two modelling approaches can capture the seismicity associated with land uplift and earthquake swarms in recent decades. This also improves hazard assessment

GFZ Helmholtz-Zentrum für Geoforschung

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image: 

View of Naples from the Hermitage of Camaldoli with Mt. Vesuvius, Gulf of Naples, Sorrento Peninsula and the Eastern edge of Campi Flegrei. Taken whilst setting up measuring stations.

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Credit: Simone Ceska, GFZ

Summary

The Phlegraean Fields volcanic complex, located beneath the metropolitan area of Naples – a city of 900,000 inhabitants in Italy – has been rising increasingly since 2005, accompanied by a growing number of small earthquakes. This development has been attracting increasing attention in the densely populated region for years. Although such phases of uplift and subsidence have occurred there for over a thousand years, the relationship between ground uplift and seismic activity is complex and not yet fully understood. A recent study in the Nature journal Communications Earth and Environment now shows that the long-term trend in earthquake activity can be well explained by combining changes in stress within the Earth’s crust with the friction behaviour of geological faults. The additionally observed swarms of earthquakes can be explained, at least in part, by interactions between individual earthquakes and successfully modelled as superimposed sequences of aftershocks.

The research team led by PD Dr Sebastian Hainzl from the GFZ Helmholtz Centre for Geosciences has successfully replicated the observed earthquake patterns of recent decades by combining long- and short-term modelling approaches. To this end, they analysed earthquake catalogues and elevation measurements dating back to around 1905. A test showed that the model is also suitable for short-term, probabilistic predictions, particularly regarding the expected earthquake rate and maximum magnitude over periods ranging from weeks to months. The study thus provides an important new tool for better assessing seismic hazard in the Campi Flegrei area.

Uplift cycles in Campi Flegrei

Beneath the conurbation of the 900,000-strong metropolis of Naples lies a complex magmatic system comprising various reservoirs in the Earth’s crust and upper mantle. For centuries, magmatic and hydrothermal processes in Campi Flegrei have led to recurring phases of ground uplift and subsidence, which are frequently accompanied by increased seismic activity. Occasionally, these cycles culminate in volcanic eruptions that form new maars or cones. The last eruption occurred in 1538 at Monte Nuovo following uplift phases between 1400 and 1536 that resemble the current situation.

Since 2005, the ground has been rising again, by more than a metre so far, accompanied by an accelerating rate of shallow earthquakes, which is causing concern given the dense population. Similar phases of uplift also occurred in the 20th century – particularly in the years 1950–52, 1969–72 and 1982–84. In some cases, these even led to evacuation measures due to the increased seismic activity.

The long-term phenomenon of land uplift and seismicity is attributed to the increase in pressure within a gas-rich reservoir at a depth of 3–4 kilometres, rather than to magma intrusion.

New study examines the seismicity patterns of the region

In their latest study, PD Dr Sebastian Hainzl, a researcher in GFZ Section 2.1 ‘Physics of Earthquakes and Volcanoes’, Prof. Dr Torsten Dahm, head of the same section, and Dr Anna Tramelli from the Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV), investigate the cause of the distinctive seismicity patterns in the region. Their analysis is based on modelling the data from earthquake catalogues and surface deformation. The latter originate from long-term leveling measurements dating back to 1905, as well as from short-term data from the RITE GPS station located at the same site. The seismicity data are drawn from various earthquake catalogues: since 2005 from the local catalogue of duration magnitudes provided by the Observatorio Vesuviano; over a longer timescale from the HORUS catalogue of homogenised moment magnitudes for earthquakes in Italy since 1960.

To investigate the mechanisms behind the observed phenomena, the research team compared and combined various modelling approaches.

Long-term developments: ground uplift and earthquakes

The study shows that seismic activity in the Campi Flegrei is closely linked to ground uplift. However, the earthquake rate is not simply proportional to the uplift rate; since 2005, it has shown a distinctly non-linear, accelerated response. The researchers demonstrate that whilst the Kaiser effect, known from rock mechanics, explains the fundamental relationship between uplift and seismicity over the last 100 years, it is not sufficient for a detailed description. The continuously accelerating seismic activity, i.e. the non-linear relationship between uplift and seismicity, can instead be explained by the friction and fracture behaviour known from laboratory experiments. This is where the so-called RS model (Rate-and-State model) comes into play.

Short-term developments: earthquake swarms

Whilst the long-term seismicity trend correlates with uplift and can be explained by stress build-up in the rock, this does not apply to the swarm earthquakes observed on a short timescale. These swarms do not correlate with land uplift and are likely linked to episodic fluid intrusions and earthquake interactions.

“We were able to show for the first time that these earthquake swarms can be explained, at least in part, by interactions between individual events and that they possess typical characteristics of tectonic aftershock sequences,” explains Sebastian Hainzl.

The standard model for the statistical description of earthquake interactions is the so-called Epidemic-Type Aftershock Sequence Model (ETAS).

Innovative modelling approach: combination of two models

To capture both the physics of long-term stress-induced changes and the statistical characteristics of short-term earthquake clustering, the researchers combined the RS model for describing the time-dependent background rate with the ETAS earthquake interaction model for the earthquake swarms.

“With this combination, we were able to successfully model the long-term occurrence of the observed larger earthquakes with magnitudes M>3 since 1960, as well as the more detailed observations of activity with smaller magnitudes M>0.5 since 2005,” summarises Hainzl.

Promising forecasting tool

Forecasting tests based on historical data show that the developed combined model enables probabilistic short-term forecasts of earthquake rates and maximum magnitudes. “This hybrid modelling approach therefore represents a promising tool for improving seismic hazard assessment in Campi Flegrei and possibly also in other volcanic systems,” says Hainzl.

Original publication

Hainzl, S., Dahm, T. & Tramelli, A. A deformation-driven earthquake interaction model for seismicity at Campi Flegrei. Commun Earth Environ 7, 244 (2026). https://doi.org/10.1038/s43247-026-03296-3

Figures

Fig. 1:

View of Naples from the Hermitage of Camaldoli with Mt. Vesuvius, Gulf of Naples, Sorrento Peninsula and the Eastern edge of Campi Flegrei. Taken whilst setting up measuring stations.

Photo: Simone Cesca, GFZ

ALT: Urban area at the foot of a mountain, with further mountains and the sea in the background.

Link: https://media.gfz.de/gfz/wv/pm/26/20260325_PM_Campi-Flegrei-Kombi-Modellierung_Blick-Campi-Flegrei_c-Simone-Cesca.jpg
 

Fig. 2

Top left: Map of the region showing earthquakes of magnitude M>0.5 that have occurred since 2005. The graph below shows the subsidence and uplift measured at the RITE station since 1905, compared with M>3 earthquakes recorded since 1960. On the right are the results of the prediction test for the number of earthquakes and the magnitude of the largest earthquake within a one-week time window, with the starting point always shifted by one week. The hatched areas describe the confidence intervals of the probabilistic predictions.

Figures: from Commun Earth Environ 7, 244 (2026). https://doi.org/10.1038/s43247-026-03296-3

ALT: Top left: Map of the region; blue dots show where earthquakes of magnitude M>0.5 have occurred since 2005. Bottom left and right: Diagrams with various curves – measured data are compared with simulated data.

Link: https://media.gfz.de/gfz/wv/pm/26/20260325_PM_Campi-Flegrei-Kombi-Modellierung_Grafik-Erdbeben-und-Modellierung_c-paper.png

 

Scientific contact:

PD Dr Sebastian Hainzl
Section 2.1 Physics of Earthquakes and Volcanoes
GFZ Helmholtz Centre for Geosciences
Phone: +49 331 6462-1897
Email: hainzl@gfz.de

Prof. Dr Torsten Dahm
Head of Section 2.1 Physics of Earthquakes and Volcanoes
GFZ Helmholtz Centre for Geosciences
Phone: +49 331 6462-1200
Email: torsten.dahm@gfz.de

 

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Journal

Nature Communications

DOI

10.1038/s43247-026-03296-3 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

A deformation-driven earthquake interaction model for seismicity at Campi Flegrei

 

U-M study reveals nitrile and latex gloves may cause overestimation of microplastics

University of Michigan

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Residue from nitrile or latex gloves may unintentionally contaminate lab equipment scientists use to measure microplastics in air, water and other samples with non-plastic particles called stearates. Stearates, a kind of salt, are chemically similar at the structural level to microplastics. They also look similar visually.

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Credit: Madeline Clough/University of Michigan

ANN ARBOR—Nitrile and latex gloves that scientists wear while they are measuring microplastics may lead to a potential overestimation of the tiny pollutants, according to a University of Michigan study.

The study found that gloves may unintentionally contaminate lab equipment scientists use to measure microplastics in air, water and other samples with nonplastic particles called stearates. U-M researchers Madeline Clough and Anne McNeil suggest cleanroom gloves, which release fewer particulates, be worn instead.

Stearates are salts, or soap-like particles. Manufacturers coat disposable gloves with stearates to make them easier to peel from the molds used to form them. But stearates are also chemically very similar to some microplastics, according to the researchers, and can lead to false positives when researchers are looking for microplastic pollution. 

That's not to say that there is no microplastics pollution, the U-M researchers are quick to say. 

"We may be overestimating microplastics, but there should be none," said McNeil, senior author of the study and U-M professor of chemistry, macromolecular science and engineering, and the Program in the Environment. "There's still a lot out there, and that's the problem."

Clough said, "As microplastic researchers looking for microplastics in the environment, we're searching for the needle in the haystack, but there really shouldn't be a needle to begin with."

The work, led by Clough, a recent doctoral graduate, is published in the journal RSC Analytical Methods. The study was supported by a grant from the U-M College of Literature, Science, and the Arts' Meet the Moment Research Initiative.

A wild microplastics goose chase

The study began when Clough was working on a collaborative project that included graduate students and faculty in the U-M departments of Chemistry, Statistics and Climate and Space Sciences Engineering to examine microplastics in Michigan's atmosphere. To do this, Clough and McNeil turned to study collaborators U-M professor of chemistry Andy Ault and graduate students Rebecca Parham and Abbygail Ayala to assist with air sampling. 

The researchers used air samplers which are fitted with a metal substrate. Air passes through the sampler, and particles from the atmosphere deposit onto the substrate. Then, using light-based spectroscopy, the researchers are able to determine what kind of particles are found on the substrate.

Clough prepared the substrates while wearing nitrile gloves, which is recommended by the guidance of literature in the microplastics field. But when she examined the substrates to estimate how many microplastics she captured, the results were many thousands of times greater than what she expected to find.

"It led to a wild goose chase of trying to figure out where this contamination could possibly have come from, because we just knew this number was far too high to be correct," Clough said. "Throughout the process of figuring it out—was it a plastic squirt bottle, was it particles in the atmosphere of the lab where I was preparing the substrates—we finally traced it down to gloves."

The researchers designed an experiment to figure out how widespread the problem is. They tested seven different kinds of gloves, including nitrile, latex and cleanroom gloves, as well as the most common techniques that microplastic researchers are using to identify microplastics. 

The experiment mimicked the type of contact that would occur in a research environment between a researcher's gloved hand and a point of contact. This would include a filter or a microscope slide—any piece of technology that a researcher might use over the course of investigating microplastics.

They found that on average, the gloves imparted about 2,000 false positives per millimeter squared area. 

"The type of contact we tried to mimic touches upon all varieties of microplastics research," Clough said. "If you are contacting a sample with a gloved hand, you're likely imparting these stearates that could overestimate your results."

The researchers also found that cleanroom gloves imparted the fewest particles—likely because cleanroom gloves are manufactured without the stearate coating, allowing them to be used in "ultrapure" applications.

Weeding out false positives

The researchers designed another experiment to determine whether they were able to distinguish what a true microplastic looked like versus one of the stearate salts from the gloves. Using scanning electron microscopy as well as light-based microscopy, they found that the stearate was visually impossible to distinguish from polyethylene, the plastic it resembles.

But Clough and McNeil were also able to find methods, in collaboration with graduate student Eduardo Ochoa Rivera and U-M professor of statistics Ambuj Tewari, that can differentiate between the false positives coming from the glove and microplastics in the environment. This can help researchers revisit potentially contaminated datasets.

"For microplastics researchers who have these impacted datasets, there's still hope to recover them and find a true quantity of microplastics," Clough said.

The researchers say their study highlights the importance of chemistry researchers in the field of microplastics who might be able to recognize the difference in chemical structure of plastics versus other contaminants.

"This field is very challenging to work in because there's plastic everywhere," McNeil said. "But that's why we need chemists and people who understand chemical structure to be working in this field."

 

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Journal

Analytical Methods

Article Title

Avoiding and Reducing Microplastic False Positives from Dry Glove Contact

Article Publication Date

26-Mar-2026

 

Scientists developed room-temperature, zero-power infrared sensor for next-generation night vision

Wafer-scale single-crystal film and clever device design enable low-cost, uncooled infrared imaging

Science China Press

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image: 

The photograph shows a one-inch, single-crystal lead sulfide (PbS) film wafer (left). The right panel demonstrates a clear infrared image of a university emblem and Chinese characters, captured at room temperature with the new detector without any cooling or external power.

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Credit: ©Science China Press

Infrared (IR) detection is crucial for night vision, medical imaging, and autonomous vehicles. However, high-performance IR sensors typically require bulky, energy-intensive cooling systems to operate, limiting their widespread use and increasing costs.

A team of scientists from Wuhan University and collaborating institutions has now developed a breakthrough IR sensor that works efficiently at room temperature and without any external power supply. Their study, published in Science Bulletin, combines two key innovations.

First, the team used chemical vapor deposition to grow wafer-scale, single-crystal films of lead sulfide (PbS) on a strontium titanate substrate. This process produces a high-quality material with minimal defects, which is essential for sensitive light detection.

Second, they designed a novel asymmetric electrode structure for the device: one side uses a chromium-gold (Cr/Au) contact, while the other uses a transparent indium zinc oxide (IZO) electrode. This configuration creates a built-in electric field at the PbS/IZO interface. When IR light hits the device, this field efficiently separates the generated electrical charges, producing a strong signal without needing an external battery.

The resulting detector shows excellent performance: a fast response time below one millisecond, high sensitivity at near-infrared wavelengths, and the ability to generate clear images at room temperature. The team successfully demonstrated this by imaging a patterned mask using only the ambient temperature of the lab.

“This work overcomes the traditional cooling barrier for lead-based infrared detectors,”said corresponding author Yao Wen. “By integrating high-quality material growth with smart device engineering, we provide a scalable path toward low-cost, uncooled infrared imaging systems for future applications.”

This advancement could significantly reduce the size, cost, and power consumption of IR cameras, potentially integrating them into everyday consumer electronics, advanced driver-assistance systems, and portable medical devices.

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Journal

Science Bulletin

DOI

10.1016/j.scib.2026.02.023 

Method of Research

Experimental study

 

Medieval DNA reveals trans-Saharan connections, rapid genetic mixing, and leprosy in Islamic Ibiza

Stockholm University

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Medieval Ibiza was far from a quiet Mediterranean backwater. New DNA evidence shows that the island was part of a dynamic world linking Europe, North Africa and even the Sahel zone, south of Sahara. An international research team led from the Centre for Palaeogenetics (CPG), a joint venture between Stockholm University and the Swedish Museum of Natural History, has revealed that its population was remarkably diverse, connected to Europe, North Africa, and sub-Saharan Africa through trade, migration, and social networks. The study is published in Nature Communications.

By analysing ancient DNA from 13 individuals buried in a tenth- to twelfth-century Islamic cemetery, the researchers found a wide spectrum of genetic ancestries, ranging from predominantly European to predominantly North African. This reflects varying degrees of mixing following the Muslim conquest of Ibiza in 902 CE. Historical sources describe two major demographic waves shaping the island: an initial settlement linked to the Umayyad expansion, and a later influx connected to the Almoravid conquest in the early twelfth century.

Two individuals carried sub-Saharan African ancestry, one tracing back to present-day Senegambia, the other to southern Chad, providing biological evidence of trans-Saharan military and/or slave networks recorded in medieval Arabic texts.

“These genomes show that people from both western and central Sahel became part of communities in Islamic Iberia,” says Ricardo Rodríguez-Varela, researcher at the Department of Archaeology and Classical Studies at Stockholm University and lead author of the study. “This is direct genetic evidence of the long-distance networks reaching the Sahel, as described in historical sources.”

Using advanced genomic techniques, including genotype imputation and haplotype-based local ancestry analysis, the team estimated that North African gene flow into Ibiza began only two to seven generations earlier. This places the main admixture event in the late ninth century CE.

“These genomes capture the moment when the Islamic world and the Christian societies of Iberia began to reshape each other,” says Anders Götherström, senior author of the study and leader of the archaeogenetics research group at the Centre for Palaeogenetics. “With ancient DNA we can begin to see how these large historical processes unfolded in the lives of real people.”

The study also screened for infectious agents. One individual was infected with Mycobacterium leprae, the bacterium responsible for leprosy, marking the first genetically confirmed case from medieval Islamic Iberia. His burial conformed to standard Islamic practices, with no signs of exclusion.

“There is no evidence in the burial context that he was treated differently from others, a pattern also reported in contemporaneous Christian communities,” says Zoé Pochon, researcher at the Department of Archaeology and Classical Studies at Stockholm University, co-author and metagenomics specialist.

Phylogenetic analysis places the M. leprae genome near the base of a lineage found across Europe between the seventh and thirteenth centuries, alongside an early-diverging genome from Italy. This suggests that Ibiza was part of wider epidemiological networks, and highlight the potential dispersal of leprosy lineage from the Mediterranean into Europe.

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Journal

Nature Communications

DOI

10.1038/s41467-026-70615-9 

Method of Research

Data/statistical analysis

Subject of Research

Human tissue samples

Article Title

Analysis of medieval burials from Ibiza reveal genetic and pathogenic diversity during the Islamic period

Article Publication Date

26-Mar-2026