The impact of earthquakes on the Earth’s surface

Activity Introduction

The activity begins by questioning students about possible causes for the occurrence of earthquakes.

A short excerpt from the film “The Impossible” is shown, which is based on the 2004 earthquake in Sumatra.

After the viewing, the file “sumatra_2004.kmz” is explored, which relates to the event seen in the video. As a class, the various data presented in the file are examined, such as:

• Epicenter

• Magnitude

• Damage caused

• Locations affected by the tsunami

• Distances from the epicenter

Seismic events are explored using the same file by activating the “Seismic Events” layer. These events are related to tectonic plate boundaries (KMZ available on the drive: limites_placas_tectonicas.kmz) and the different types of boundaries, referring to divergent, convergent, and other types. A connection is made between the tectonic plate boundaries and the plate on which Portugal is located. Students are questioned about the different types of plate boundaries.

The video “240 million years ago to 250 million years in the future” by Chris Scotese, professor in the Department of Earth and Planetary Sciences at Northwestern University (USA), is explored. The video simulates tectonic plate movement from 240 million years ago to 250 million years into the future.

Activity Development

After exploring the KMZ files mentioned, protective measures against the effects of earthquakes are discussed with the students. They are also asked about existing detection methods that could anticipate an event like the one seen in the movie.

Students are then challenged to build a seismograph in groups, with warnings about the proper use of tools like the hot glue gun (which will be shared among all groups).

The class is divided into groups of 4 to 5 students, the student guide is handed out, and step 1 is projected to analyze the main steps in building a seismograph. Each group receives the following materials:

• Transparent plastic cup

• Magnet

• Crocodile clips

• Micro:bit and USB cable for computer connection

• Computer with Office 365 and the Hacking STEM Data Streamer module

• Cork stopper

• Plastic plate

• Copper wire

Teachers assist students in building the seismograph and ask the groups questions about previously discussed topics, such as:

• What is the function of seismographs?

• What is the purpose of seismograms?

• What is the difference between hypocenter and epicenter?

• What is the relationship between the energy released at the hypocenter and the behavior of seismic waves?

• What is the difference between magnitude and intensity?

• What are the consequences of earthquakes?

After construction, students are asked to connect the micro:bit with the seismograph to the computer, open Excel with the Data Streamer module, and follow the instructions in the student guide to start collecting data from the seismograph by simulating an earthquake (shaking the plate or table).

Students are then asked to complete task 2 from the student guide.

For task 3, students use the PhET simulation plate-tectonics_pt_BR.jar to explore the density differences between different lithospheric plates, using various tools (density, temperature, and thickness measurements) and examining the consequences of interactions between different types of plate boundaries. The simulation is projected at the front of the classroom, with some features demonstrated, and a student is asked to use the projection to explore the density in a specific location. Questions posed include:

• In a convergent movement between equal plates, when the density of plate A is greater than that of plate B, what is the expected result? Justify your answer.

• In a convergent movement between equal plates, when the densities of plates A and B are equal, what is the expected result? Justify your answer.

• In a convergent movement between a continental crust plate and an oceanic crust plate, what is the expected result? Justify your answer.

Two tablets with the application installed are distributed per group, and students are asked to explore other features and draw conclusions related to material density, using temperature, density, and thickness as factors. The teacher circulates among the groups and questions them about the different outcomes obtained from the simulation variables.

Before students complete task 4 from the guide (on seismic waves), the animation “2004 Sumatra Quake & Tsunami” by the Incorporated Research Institutions for Seismology is shown. The animation is discussed with the students, with questions about P and S waves. Students are asked about the area affected by the earthquake, establishing the relationship between the similarity ratio of figures and the ratio of perimeters/areas.

In task 4, students use Google Earth to measure distances between points:

Activity Conclusion

A national context is introduced by creating a hypothetical case from the following question:

“If a magnitude 9 earthquake on the Richter scale occurred in Lisbon, would a resident of Mangualde have time to prepare for its impact there?”

The following data table is presented and discussed.

Students are questioned about the distance from Lisbon to Mangualde and are encouraged to verify it using Google Earth. Based on the analysis of the table and the distance, the initial question is asked again. Students are asked to explain their reasoning.