Why does the Earth shake in the Azores? From the São Jorge seismic-volcanic crisis to blue carbon

The most energetic earthquake since the beginning of the crisis had a magnitude of 4.1 on the Richter scale.

CIVISA (Azores Seismic and Volcanic Information and Surveillance Center) stated this Sunday that São Jorge, in the Azores, continues to experience seismic activity “well above” what is “considered normal,” despite a “lull” in felt tremors, reiterating that “all scenarios are on the table.”

The coordinator of CIVISA operations in São Jorge emphasized that since March 19, the start of the crisis, seismic records have been “far above what is considered normal,” even “compared to all seismic activity in the rest of the archipelago.”

“In total, since the start of the crisis, we have recorded 26,348 earthquakes and a total of 225 felt tremors. The depths remain in the range between 7 and 13 kilometers, as has been previously reported,” she added.

She stated that “all scenarios” remain “on the table,” including the possibility of a volcanic eruption or a higher magnitude earthquake.

About 2,500 people have already left the municipality of Velas, the center of the seismic crisis—1,500 by air and sea, and the rest to the neighboring municipality of Calheta, considered safer by experts.

Adapted from CNN Portugal. (2022). Sismicidade em São Jorge continua acima do normal apesar da “acalmia”. Nas últimas 24horas, registaram-se 603 sismos. Accessed April 5, 2022.

The current situation in the Azores demands knowledge in multiple areas in order to monitor and respond effectively, especially in the event of an evacuation. It also requires special attention to CO₂ emissions, as this greenhouse gas contributes to global warming. One area under active research to address this problem is algae cultivation for CO₂ sequestration.

Throughout the morning, you will take on the role of a scientist to learn more about earthquakes and volcanoes and to study solutions that help mitigate climate change.

Section A

1. Considering the seismic-volcanic crisis that began in March on São Jorge Island, answer the following questions:

1.1 Do some research in your textbook and/or online, and explain the meaning of the phrase “a magnitude of 4.1 on the Richter scale” as taken from the text.

1.2 What is the likely cause or causes of the high number of earthquakes recorded in the Azores?

1.3 Many earthquakes are not felt by the population. Explain how we know they occurred.

1.4 A seismic crisis like this can be associated with an impending volcanic crisis. Explain how the monitoring of an active volcano is carried out and why it is important.

2. Sumatra Earthquake – Open the KMZ file “Sumatra 2004” and analyze the impact of the earthquake in terms of death toll in distant places like Sri Lanka, the Maldives, Seychelles, and others. Check the distance between the Sumatra earthquake epicenter and the mentioned locations.

2.1 Imagine that an earthquake of similar magnitude occurred in the Azores. What would be the likely impact on mainland Portugal? Explain your answer.

Section B1

As you saw in the RTP video at the beginning of the session, there is a team responsible for measuring carbon dioxide (CO₂) in the soil. This is a substance essential to life on Earth and has a direct responsibility in the planet’s greenhouse effect. It is also a cause of concern for the scientific community since the high concentration of CO₂ in the atmosphere causes serious climate imbalances. This happens because CO₂ is the greenhouse gas that contributes the most to  global warming. Scientists are studying ways to mitigate this issue through CO₂ sequestration and conversion into clean energy solutions.

Open the following news articles on your computer/tablet:

1. CO2 vira combustível líquido com sistema de baixo custo
2. O oceano e o sequestro de carbono: aproveitando o potencial de captura de carbono do oceano

Now, based on those articles, answer the following:

• How can human intervention help mitigate the high concentration of CO₂ in the atmosphere?

• What is the importance of oceans in CO₂ sequestration (blue carbon)?

Now that you understand the importance of oceans in CO₂ capture—particularly that microalgae (phytoplankton) and macroalgae absorb CO₂ and release oxygen through photosynthesis—let’s analyze the following word equation related to this process:

water (l) + carbon dioxide (g) ===>>> glucose (aq) + oxygen (g)

Read and interpret the word equation.

Section B2

As seen in the video shown at the start of class, a seismic crisis can lead to a volcanic eruption. You will simulate a volcanic eruption by doing a practical activity.

Materials:

Ammonium dichromate, sugar, salt, iron filings, match heads, “volcano cone”

Procedure:

1. In the cone, place a layer of ammonium dichromate (about 1.5 tablespoons), sugar, salt, iron filings, and 7 match heads, mixing everything;

2. Place a final layer of ammonium dichromate (1 tablespoon), and stick 8 matches deep into the cone, leaving just the heads visible;

3. Light a match and throw it into the cone;

4. Observe the “eruption” and record the results using an appropriate diagram.

A) Results analysis

B) Conclusions (Include the factor that triggered the reaction in your conclusions)

Section C1

Carefully analyze the data presented in the Power BI dashboard related to the magnitude and depth of all earthquakes in the Azores between March 19 and April 18, 2022.

In the previous table, we can see that only one event occurred at 27 km depth. It’s also confirmed that 29 earthquakes were recorded at a depth of 8 km.

1.1 How many earthquakes had their hypocenter at a depth of 11 km?

1.2 Relate the depth of the hypocenter with the possibility of surface damage.

1.3 What are the modes of the two variables being studied?

1.4 Based on the previous question, was there any destruction of landscape (landslides, tree falls, etc.) or human structures (collapse of bridges, poles, buildings…)? Justify your answer using the Power BI data.

1.5 Calculate the average magnitude of the earthquakes that occurred in São Jorge during the period analyzed.

1.6 Was the average magnitude of the earthquakes high or low during the considered period? What importance should be attributed to this measure? Can a low average value reassure us? Justify your answer based on the concept of average and earthquake magnitude.

Section C2

CO₂ is one of the gases released during volcanic eruptions and is one of the main contributors to the greenhouse effect. If, following the current seismic-volcanic crisis, a volcanic eruption in São Jorge occurred similar to the Cumbre Vieja eruption in the Canary Islands—with average daily emissions of  800 tonnes de CO2, what CO₂ sequestration measures could be taken by the Azores regional government? Since the Azores is an archipelago, the ocean could play a fundamental role in this sequestration process, aligned with a blue carbon strategy.

Analyze the following articles to answer the questions presented:

1. O oceano e o sequestro de carbono: aproveitando o potencial de captura de carbono do oceano
2. O maior lago de crescimento de algas do mundo usa tecnologia baseada na natureza para capturar as emissões de CO2
3. Revisão do estado da tecnologia – Bioenergia de algas
4. Fertilização com algas
5. Produção de rações com algas reduzem as emissões de metano em 20%

Reference value for CO₂ sequestration using fresh macroalgae:

1 kg of CO₂ is sequestered by 10 kg of fresh macroalgae

1.1 If the São Jorge volcano remains active for two months (considering each month as 30 days), calculate the amount of CO₂ released in this period.

1.2 Determine the mass, in tonnes, of fresh macroalgae that would need to be cultivated to sequester all the CO₂ emitted in the eruption.

1.3 Considering that the ratio between the mass of dry macroalgae and fresh macroalgae is 1/10, calculate the amount, in tonnes, of dry macroalgae needed to sequester all the CO₂ released by the volcano into the atmosphere.

Conclusions

Currently, various companies around the world are developing solutions related to blue carbon for mitigating climate change, such as Brilliant Planet (UK), as well as others in Portugal. These include both direct CO₂ capture and indirect methods—like producing animal feed that reduces methane emissions or creating non-chemical general-use fertilizers.

Prepare an informative text for the Municipality of Mangualde about these solutions, such as those presented by the company Genesis Algae Innovation, as a way of sharing ideas for local economic development linked to blue carbon. In your proposal, consider the following:

A) Explain their importance in CO₂ sequestration.

B) Since Mangualde is a region where the primary sector (agriculture and livestock farming) is very important to the local economy, explain how this company could contribute to this sector.