Tag: Environment

New research shows analysis of seismic data reveals Hamas’ movements on October 7th.

A groundbreaking study in the field of forensic seismology, conducted by Tel Aviv University researchers, has identified the seismic signature of Hamas forces’ movement before the October 7th attack. Researchers from the Department of Geophysics at Tel Aviv University’s Porter School of the Environment and Earth Sciences and Sackler Faculty of Exact Sciences recently analyzed data recorded at three seismic stations in southern Israel. The findings reveal that on the morning of October 7th, approximately half an hour before the deadly terrorist assault, the stations recorded weak but widespread human-induced seismic noise. The researchers attribute these anomalous seismic amplitudes to the unusual movement of heavy vehicles within the Gaza Strip heading toward organizational points along the Israeli border up to 20 minutes before the ground barrier breach.

The researchers explain that forensic seismology is often used to monitor conventional and nuclear explosions. However, this is the first time in history that weak ground motions resulting from preparations for a terrorist attack have been identified by analyzing the characteristics of seismic noise induced by vehicular traffic. They believe the discovery demonstrates the potential usage of seismic-based sensing technology to provide early warnings of terrorist activity. However, they emphasize that the identification of these movements in Gaza was conducted retrospectively, months after the attack.

The study, led by Dr. Asaf Inbal of the Department of Geophysics at Tel Aviv University’s Porter School of the Environment and Earth Sciences and the Faculty of Exact Sciences, was published in The Seismic Record, a journal of the Seismological Society of America.

Dr. Inbal explains: “The Israeli Geological Survey operates a nationwide network of dozens of highly sensitive seismometers that continuously monitor ground motions. This network is primarily designed to detect and locate earthquakes and warn of strong ground shaking caused by large-magnitude seismic events. However, three stations in the network—located in Amazia, Ktsiot, and Yatir, between 30 and 50 kilometers from Gaza—recorded unusual seismic noise levels early in the morning of October 7th, 2023. This noise can be attributed with confidence to the vehicular activity in Gaza as Hamas terrorists gathered for the attack. The time frame was between 6:00 and 6:30 AM, before the rocket fire began. The likelihood that the recorded signals originated from Gaza is over 99.9%”.

Detecting Terrorist Preparations with Seismic Waves

Although the seismometers are designed to detect extremely weak ground motions, Dr. Inbal points out that the ability to link the seismic noise to Gazan vehicle movements was facilitated by the quiet background seismic noise levels that prevailed in southern Israel during the early hours of that Saturday morning, which coincided with the holiday of Simchat Torah.

“The motions recorded near the seismometers were in the range of tens of nanometers per second, whereas the minimum ground motion detectable by humans is several millimeters per second”, explains Dr. Inbal.

“The characteristics of the noise originating from Gaza and captured by the Israeli stations are fundamentally different from those recorded at the same stations on previous Saturdays during those hours. We analyzed three years of data from the Israeli station trio recorded in the same time frame as the one leading up to the attack. We found no instance of a Saturday morning when correlated amplitudes were recorded at all three stations for over 10 minutes. It’s important to note that these stations are widely spaced, with each station primarily sensitive to seismic noise generated by nearby human activity. For instance, the distance between Ktsiot and Amazia is about 80 kilometers, and on previous Saturdays, there was no correlation between the data recorded at these stations. On the morning of the attack, when local activity near the stations was minimal, we found unique widespread seismic amplitudes, which monotonically increased with time approaching the attack. No known natural or human source on the Israeli side could have generated seismic signals with a distribution and intensity similar to those attributed to Hamas movements. Although the outdoor music festival near Re’im generated some seismic noise, our analysis shows that this noise does not match the strength or location of the noise sources recorded by the Israeli seismic network on October 7th”.

Findings from the research.

New Insights Into Hamas’ Movements on October 7th

The analysis indicates the seismic noise detected began at 6:00 AM and intensified as the attack approached. Occasionally, the noise contained short bursts strong enough to pinpoint their source and track their progress. The location and intensity of these sources in Gaza suggest vehicle movements advancing southward and northward within Gaza, from Rafah in the south to the Erez crossing in the north, during the 30 minutes leading up to the attack.

“We have good resolution along Salah al-Din Road, a major thoroughfare crossing Gaza from Rafah in the south to Beit Lahia in the north”, says Dr. Inbal. “We can confirm with high certainty that their forces moved along this route at speeds of 25 to 50 km/h. Observations from stations dozens of kilometers from Gaza’s border indicate convoys of heavy vehicles such as bulldozers and trucks carrying operatives. Three minutes before the attack began, we detected noise sources reaching the northern end of Gaza near Beit Lahia and the southern end near Khan Yunis. At the same time, we continued receiving signals from central Gaza, near Nuseirat. We know the assault began almost simultaneously along the entire border, so these seismic observations provide further evidence of the extensive deployment of Hamas forces, likely enabling the simultaneous breach of the ground barrier”.

Dr. Inbal concludes: “This development results from five years of seismological research aimed at characterizing seismic noise generated by human activities. I hope this new knowledge will lead to the expanded use of such tools for both security and industrial purposes”.

“We see graduates of the Department of Geophysics at Tel Aviv University playing a leading role in scientific and technological advancements, and we are confident that in the future, multi-purpose seismic-sensing technologies will be more widely used in various fields that impact our daily lives” – Dr. Inbal.

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TAU post-doc Tamar Elman is creating a startup to harness hydrogen gas produced by algae during photosynthesis.

Recent reports that 2023 was the world’s hottest year on record highlights the urgency of mitigating climate change. One unavoidable change will be to clean up the energy sector, which currently produces 70% of industrial waste including greenhouse gases and ozone-eroding chemicals. The solution may come in the form of a tiny single-celled organism which most may recognize as the green layer on top of lakes and ponds: algae. Tamar Elman, a Tel Aviv University post-doctoral researcher in the lab of Iftach Yacoby at the Wise Faculty of Life Science, has discovered a microalgae species with a mutation which produces large amounts of hydrogen gas, a promising clean energy source. After completing a course at TAU’s Entrepreneurship Center, she is building a startup to figure out how this hydrogen production might be harnessed and industrialized.  

An Accidental Discovery  

Hydrogen gas is a very clean source of energy because its only byproduct is water vapor. “Unfortunately,” says Elman, “because it does not naturally accumulate anywhere in large amounts, producing hydrogen gas in a usable form does produce carbon waste. So there is a race right now to create a totally green production method that is also scalable and profitable.” 

“There is a race right now to create a totally green production method that is also scalable and profitable.”

One natural source of hydrogen gas is microalgae, which is found in most habitats around the world and grows easily. In 2021, Elman was trying to increase the small amounts of hydrogen gas produced by microalgae in the TAU Yacoby lab. “Microalgae are considered plants because they perform photosynthesis, using solar energy to transform carbon dioxide into sugars for nourishment. However, green algae also have a built-in “circuit breaker” that burns off any excess solar energy by converting it to hydrogen gas. Unfortunately, hydrogen production is usually shut down quickly by other functions of the algae.  

One day, Elman and Prof. Yacoby tested a new culture and saw the hydrogen levels reaching unprecedented heights. “We thought we were seeing a mistake in the hydrogen measuring device. We almost threw out the culture!” Says Elman. “But when we tried it on a different device and got the same results, we realized we had found a mutated algae strain that naturally overcame the barriers to continued hydrogen gas production.” 

Scaling Up 

Upon publishing a paper in 2022 on their discovery, Elman and Prof. Yacoby garnered quite a bit of interest from the scientific community. The two decided to capitalize on the buzz, delving further into experimentation on their mutation. Elman also won a grant from the Israeli Innovation Authority which required she take a course on breaking into industry at TAU’s Entrepreneurship Center. 

Elman and Yacoby nailed down their idea to produce hydrogen gas for the energy sector and to work with the food industry to sell the used algae, which is left with high nutritional value after the production process.  

Elman and Prof. Yacoby hope to industrialize microalgae-based hydrogen gas production. (Photo: Tel Aviv University)

The two discovered that scaling up creates its own host of challenges, as processes that work at small scales may not always translate proportionally. Elman realized she would need a very simple way to induce hydrogen production in the algae. “It’s almost comical how basic this method is,” she says of her solution. “All I do is give the algae some concentrated acid and let them sit in the dark for two hours breathing oxygen. Then I open the windows to let light in, and the algae start producing hydrogen! It’s practically too simple to market, but it really works.”  

Elman spent the last year gathering her data and creating material for investors and industry stakeholders with the help of her Entrepreneurship Center team. Now, she is meeting with investors. “Even though it’s very difficult, I know I would regret not trying. And it’s an amazing feeling to see my research lead to something concrete.” 

Her next steps are, she hopes, to build a large photobioreactor that can be used for larger-scale experiments and production. 

Thinking Like an Entrepreneur 

To learn what is needed to create a startup and collaborate with industry, Elman participated in a course called JumpTAU which brought together Arab and Jewish students in mixed startup-building teams at TAU’s Entrepreneurship Center. For months, the teams received intensive lectures, individual guidance and networking opportunities from industry experts and dedicated mentors. 

“Entrepreneurship is a different type of thinking. I had to figure out who my audience was and how to frame my work as beneficial to them.”

After performing scientific research for 9 years, says Elman, “entrepreneurship is a really different type of thinking. I discovered that customers and investors aren’t interested in science for science’s sake, so I had to figure out who my audience was and how to frame my work as beneficial to them. Now a year later, I have a professional slide deck I can proudly show to investors.” 

She felt particularly supported by the mentors and Center Director Yair Sakov, all of whom she says she can still turn to for ongoing counsel. “I really feel like those at the Center care about my success.” 

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TAU Research Shows that Lightning Storms are Causing Sea Ice to Melt Faster at the North Pole

A new international study with the participation of researchers from Tel Aviv University found that alongside the general warming of the globe, lightning storms have been directly hastening the ongoing process of sea ice retreat covering the Arctic Ocean. According to the researchers: “Until recently, lightning as a phenomenon was extremely rare in the Arctic region of the North Pole, due to the intense cold. However, due to the warming of the Earth, lightning storms have become more common there in the summers, and these storms further increase the melting process of the ice sheets – in a feedback loop”.

Prof. Colin Price and MSc student Tair Plotnik from the Department of Geophysics at TAU’s Porter School of the Environment and Earth Sciences participated in the study, alongside Dr. Anirban Guha and Dr. Joydeb Saha from Tripura University in India. The article was published in the journal Atmospheric Research.

Arctic’s Cold Reality: Understanding Rapid Ice Loss

Prof. Price explains: “The Arctic region is defined as the region located north of the 66.5° latitude. In the heart of this region, around the North Pole, there is no land, and due to the extreme cold conditions, the sea is covered with a thick layer of sea ice, which currently extends over about 8 million square kilometers. The white ice reflects the sun’s rays and thus contributes to the cooling of the Earth. But in recent decades, with the warming of the Earth, the ice cover has retreated at a rate of about 70,000 square kilometers per year, or 6.5% per decade (In this context, it is important to note that the temperature at the North Pole has been rising at an accelerating pace – about 4° until today, in contrast to about 1° on Earth as a whole).

Prof. Colin Price

The retreat of the ice increases the warming even further, because the dark areas of the ocean under the ice, which are getting bigger and bigger, absorb the sun’s rays that would normally be reflected in space. This is how a feedback loop is created: the retreat of the ice increases the warming, which in turn increases the melting of the ice, and the cycle repeats”.

Lightning’s Role in Polar Ice Melt

According to the researchers, the phenomenon of melting ice sheets at both poles is firstly attributed to the result of human activity due to the increase in the amount of greenhouse gases in the atmosphere, creating a kind of ‘blanket’ that preserves the heat and does not allow it to disperse into space. However, studies have not found a direct match between the greenhouse gas changes, which increase at a more or less constant rate every year, and the rate of sea ice melting, which varies immensely from year to year. This study sought to examine the possible effect of another factor – lightning storms – on the melting of the sea ice in the Arctic region.

The researchers explain that lightning, as a phenomenon, was extremely rare in the Arctic region until recently, due to the intense cold that prevails there. But in recent decades, apparently, due to global warming, lightning storms have been observed there in the summertime, when the sun does not set at all, heating the surface (Lightning storms form when the surface of the ground heats up, and pockets of air rise in the atmosphere, where they cool, condense, and become clouds that sometimes develop into thunderstorms).

To test their hypothesis that lightning storms contribute to the melting of the ice around the North Pole, the researchers compared two sets of data: images from NASA satellites that have been documenting the retreat of the ice in the Arctic Sea for more than 40 years, and lightning data collected by the global network WWLLN (wwlln.net) – which includes around 70 lightning detection stations, deployed in research institutions all over the world – one of which stands on the roof of the Faculty of Exact Sciences building at TAU. Prof. Price explains: “Lightning is the result of a massive electric field that is discharged at once and transmits radio waves that can be received even thousands of kilometers away from the lightning. The global network’s sensors detect and map thunderstorms anywhere on the planet, in real-time and non-stop. Cross-referencing the information from the various stations allows for an accurate determination of the location and time of each lightning strike detected, and thus, a global map of lightning over time is obtained. For this study, we collected data on lightning in the Arctic region during the summer months of June, July and August every year since 2010″.

Lightning Storms: Catalysts for Polar Ice Melt

A statistical analysis of the ice sheet retreat crossed with the number of lightning storms revealed a correlation: as the number of storms increased in a certain year, so did the melting of the sea ice increase that year. The researchers explain this by comparing thunderstorms to a giant vacuum cleaner, sucking water vapor up from the surface layer to the upper atmosphere (5-10km altitude), where it accumulates and acts like an additional blanket, trapping the surface heat from leaving, and increasing the surface temperature – just like man-made greenhouse gases. Another possibility observed in a previous study is that these same lightning storms lead to an increase in the formation of high cirrus clouds in the upper layers of the atmosphere – which also form a similar ‘blanket’.

Prof. Price concludes: “In our research, we found a clear statistical relationship between the number of lightning storms in the Arctic region in a certain year and the rate of sea ice melting that year. This means that the storms are another factor that increases the melting of the polar ice, producing a feedback loop: the initial melting of the ice increases the dark surface areas of the sea, which absorb more of the sun’s rays, warming up the waters, causing more melting, accelerating the rate of warming, which in turn increases the number of lightning storms, and the cycle repeats itself. As a result of this, and of the warming of the Earth in general, we expect that the frequency of lightning storms in the Arctic region will increase in the coming years, and with it, the rate of sea ice retreat in the Arctic Sea will accelerate”.