Temblores y Sensores: Relationships between Mexico’s seismic situation and faulty realities of the U.S. earthquake sensing network

Figure 1. Aztec glyph named Tlalollin meaning "movement of the earth." In Nahuatl, Tlalli means earth and ollin means movement (Lagos, 2017).

Tlalollin­– the “movement of the earth” would begin and the Aztecs start scream and shout clapping their palms to their mouths warning everyone in range that the earth is trembling. Before the earthquake finished, they would take their children by the temples and lift them up so the quaking would not carry them away or stunt their growth (Lagos, 2017). 

The Aztecs believed that there were four eras of past earths and humanity, each destroyed by flooding, fire, hurricanes, or demolishing monsters. It is prophesized that the Fifth Sun, the current world, will be completely annihilated by a series of earthquakes (Bjornerud, 2017). Mexico experienced a 7.1 earthquake in 2017 which killed 300 people, and an 8.0 magnitude earthquake in 1985 which killed 10,000. On June 23, 2020, a magnitude 7.4 earthquake hit Oaxaca taking place 14 miles off the Pacific coast near Santa Maria Xadani (Sieff, 2020). Only 10 people were killed, and around 30 buildings damaged. Hospital de Regional de Alta Especialidad de Oaxaca was one of these buildings damaged–but was also one of the few hospitals in Oaxaca prepared to care for COVID-19 patients. It was at 100% capacity (Alberto et al., 2020). Other hospitals were evacuated while a total of 1,400 aftershocks continued through the next day. Though the threat of destruction is nothing out of ordinary for Mexico, earthquakes are now exacerbating the risk of locals contracting COVID-19. While COVID-19 wreaks havoc on Mexico’s medical infrastructure, another large earthquake could collapse it (Suárez, 2020). Mexico’s earthquake predictions are no longer entirely based on prophecy however, and state officials are now taking extra measures to amplify earthquake warning signals throughout Oaxaca (Comunicado, 2020).

How is Mexico going to amplify seismic signals if earthquakes are really difficult to predict? Not that earthquakes happen out of nowhere per se, scientists know that earthquakes occur in subduction zones–areas deep in the ground where the tectonic plates meet, one sliding under the other. Along the Pacific coast of Mexico, the Cocos plate grates under the North American plate moving about one centimeter per year–building up energy from friction. Earthquakes also occur at breaks in crustal rocks called faults. Once enough energy builds up, the pressure between the crustal rocks releases throughout the earth’s crust in all directions and eventually comes in contact with different rocks creating primary and secondary waves. This is known as seismic activity. Primary waves, or P waves, occur deep in the ground and move back and forth. The physics behind P waves is similar to that of a person being pushed. Secondary, or S waves, occur on the surface and move like battle ropes for exercising. Not only do S waves inherently cause more damage, but Mexico City’s soft soil makes the waves anywhere from 10 to 500 times more powerful (Carrillo, 2019). Since the Spaniards drained Texcoco lake, 20 million citizens are left with a wet clay ground especially subject to sinking and damage caused by earthquakes (Cruz‐Atienza et al., 2018). Revised building codes and improved infrastructure may not be enough to prepare the state for an extreme earthquake (Sieff, 2020). Researchers have predicted for the past 60 years that a magnitude 8.2 earthquake is pending, making earthquake signaling just that much more important. Right now, sensors can predict the arrival of S waves within an average of 60 seconds until arrival.

 

Figure 2. Map of Mexico's Pacific coast representing tectonic movement, historical subduction thrust events, other geologic events, volcanoes and known faults (Cruz-Atienza et al. 2018).

Before the 1985 earthquake, Mexico did not have national emergency plans or drills in place. The Mexican Seismic Alert System (SASMEX) became the first system in the world to send early warnings to the public. Since 1991, SASMEX has been broadcasting alerts to Toluca, Acapulco, Chilpancingo, Mexico City, and Oaxaca (who installed its own network called SASO in 2003). How does a network this vast generate a preventative warning signal within an average of 60 seconds to spare? The network has field stations along faults and tectonic boundaries that basically take x-rays or ultrasounds of the ground. The sensors calculate the energy produced and time between the start of the first P waves until the start of the S wave. It takes a few seconds for the signals of an earthquake in the ground to reach the surface. A computer then estimates the range of the earthquake to determine how far away the warnings should be sent (Cappucci, 2020). Two alerts are chosen from, either preventative or public based on the magnitude of the earthquake. (Espinosa-Aranda et al., 2012). The government installed VHF radio transmitters to quicken the transmission of the warning signal. If radio signals travel at the speed of light (67 million mph) and P waves run 3.5 miles per second, then warnings signals can reach people quicker than the earthquake (Cappucci, 2020).

 

 

Figure 3. Seismic Alert System of Mexico diagram (Espinosa-Aranda et al., 2012).

 

The answer to how Mexico is going to amplify the seismic signals lies in improving predictions of earthquakes. While the best ways to prepare communities is by quake-proofing buildings and regulating infrastructure, predicting earthquakes will help with future risk management (Sophie Hares, 2018). The idea is to find areas in the earth’s crust where an earthquake has not happened for a while, but this is not the only determining factor. Because the pressure and energy buildup are hard to pinpoint so deep in the ground, it is difficult for researchers to know exactly where to place seismic sensors. In 2013, Kyoto University researchers, the Japanese government, Mexican government, and researchers at the National Autonomous University of Mexico collaborated to predict where the next extreme earthquake may occur. The $8 million project added 14 seismometers, 7 ocean bottom seismometers, 7 ocean bottom pressure gages and 2 GPS-acoustic sites to the SASMEX system in Mexico and Central America (Schachar, 2017). 

While Japan, Turkey, China, Taiwan, and Chile have implemented similar sensing networks, the United States has not (Mexico Has an Earthquake Warning System, What about the U.S.?, 2017). The West Coast’s current network of 500 sensors is called ShakeAlert, a program made up of contributors such as the Pacific Northwest Seismic Network, California Integrated Seismic Network, and the Advanced National Seismic System (ShakeAlert FAQ, 2018). Though ShakeAlert is designed to warn U.S.-Americans that an earthquake greater than magnitude 5 is approaching, the system does not predict earthquakes (Cappucci, 2020). An extensive prediction network would cost around $40 million with an additional $16 million annually to operate, so money plays a role in why the U.S. has yet to develop a more in-depth system (Adam, 2020). Additionally, current technology is too slow to be worth the cost of development (Cappucci, 2020). The faults in California are found inland rather than under the ocean. Some subside directly underneath major cities like San Bernardino. Even if a system were in place and quick enough, this inherent closeness to the source of the earthquake has convinced some that investing would not be entirely worth it (McPhate, 2017). The warning would come too late.

Tectonic plates meet along the entire length of the Americas. Geologically, the U.S. and Mexico share the risk of earthquakes; however, the Trump administration has been adamant about separating itself from Mexico. For the past few years, the Trump administration has directed its budgeting towards the U.S. immigration system claiming it has “come to the point of a system-wide breakdown in March 2019” (Rummler, 2019). This failure of the immigration system prompted the reallocation of $9.7 million in 2018, and an additional $155 million in 2019 from FEMA disaster relief toward ICE (Rummler, 2019). The administration also cut the U.S. Geological Survey’s budget by 20% in 2018, leaving just enough funds to operate and continue ongoing projects. The Volcano Early Warning System was entirely discontinued, as was funding for the Earthquake Warning System (Becker, 2018). While the U.S. spent over $306 billion on natural disasters in 2017, this indispensable budget is now being designated towards building more detention centers and legal hearing locations (Rummler, 2019). 

To make up for the lack of a comprehensive network in the U.S., a private company called Grillo has partnered with The Linux Foundation, Arrow, USAID, Harvard University, IBM, and Axxa to provide global open-source sensing. Grillo’s software uses machine learning to confirm earthquake predictions earlier than a stand-alone system would. The app also uses Twitter to communicate earthquake warnings to coincide with physical sirens and radio towers in Mexico. Andres Meira, the founder of Grillo, points out that “earthquakes don’t respect boundaries, political boundaries” meaning earthquakes that occur in Mexico can potentially trigger earthquakes and tsunamis in the U.S. or Central America. Forming a multinational network could address blind spots in current established national systems which would improve earthquake predictions internationally (Adam, 2020).

On a global scale, countries develop extensive sensing networks after catastrophic earthquakes occur (Mexico Has an Earthquake Warning System, What about the U.S.?, 2017). The Pacific West Coast is the most populated region of the U.S. with California being the most populated state (California’s Population, n.d.). Maybe by the time the U.S. implements a comprehensive network the world will have been completely destroyed by a series of earthquakes just as the Aztecs prophesized. Or maybe, despite Trump’s defunding of the warning system, Grillo, and its ever-growing collaborative, will take charge of the fate of more than 40 million people.

Stephanie Jiménez is a first generation Mexican American raised in Pittsburgh, PA. At the University of Pittsburgh, Stephanie is pursuing a BS in environmental science and a BA in global and popular music track as well as certificates in Latin American studies, geographical information systems, and sustainability. Drawing on their cultural background and interdisciplinary focus, Stephanie looks forward to exploring the intersections between environmentalism, science, culture,  music, and politics while writing as an intern for Panoramas. After graduation, Stephanie hopes to pursue a higher degree in agroforestry and/or ecomusicology.


References

Alberto, Y., Chen, K., Cordero, D., Craun, Z., Diaz-Fanas, G., Fischer C., E., Gabriela Haro, A., Hakhammaneshi, M., Kenawy, M., Khalil, Z., Martin, A., Nikolaou, S., Rodriguez-Nikl, T., Sadegh, J., Wang, M., Wibowo, H., & Wu, K. (2020). Virtual Earthquake Reconnaissance Team (VERT): Phase 1 Response to M7.4 Mexico City Oaxaca  06/23/2020(p. 52). http://learningfromearthquakes.org/images/earthquakes/2020_Oaxaca_Mexico...

Becker, R. (2018, February 14). How Trump’s 2019 budget would leave us vulnerable to natural disasters. The Verge. https://www.theverge.com/2018/2/14/17006424/donald-trump-2019-budget-pro...

Bjornerud, M. (2017, September 22). The Strange Tectonic Coincidence of Mexico’s September Earthquakes. The New Yorker. https://www.newyorker.com/tech/annals-of-technology/the-strange-tectonic...

California’s Population. (n.d.). Public Policy Institute of California. https://www.ppic.org/publication/californias-population/

Cappucci, M. (2020). Californians can now get earthquake early warnings on their phones. Here’s how the alerts work.Washington Post. https://www.washingtonpost.com/weather/2020/02/08/californians-can-now-g...

Comunicado. (2020, Agosto). Trabajan en agilizar reconstrucción de Oaxaca, diputados y Sedatu: Pável Meléndez. www.rioaxaca.com. https://www.rioaxaca.com/2020/08/24/trabajan-en-agilizar-reconstruccion-...

Cruz‐Atienza, V. M., Ito, Y., Kostoglodov, V., Hjörleifsdóttir, V., Iglesias, A., Tago, J., Calò, M., Real, J., Husker, A., Ide, S., Nishimura, T., Shinohara, M., Mortera‐Gutierrez, C., García, S., & Kido, M. (2018). A Seismogeodetic Amphibious Network in the Guerrero Seismic Gap, Mexico. Seismological Research Letters, 1435–1449. https://doi.org/10.1785/0220170173

Espinosa-Aranda, J. M., Cuéllar, A., Ibarrola, G., Islas, R., García, A., Rodríguez, F. H., & Frontana, B. (2012). The Seismic Alert System of Mexico (SASMEX) and their Alert Signals. Broadcast Results Paper.

Ivan Carrillo. (2019, March 7). Will the Guerrero seismic gap be Mexico’s demise? El Universal. https://www.eluniversal.com.mx/english/will-guerrero-seismic-gap-be-mexi...

Lagos, A. (2017). The earth crashed into the sun: This is how the pre-Hispanic people experienced earthquakes. From codices to náhuatl annals to the chronicles of Bernardino de Sahagún, Mexico has been recording its earthquakes for centuries. 5.

McPhate, M. (2017, September 21). California Today: Mexico Has a Quake Warning System. Where is California’s? The New York Times. https://www.nytimes.com/2017/09/21/us/california-today-mexico-has-a-quak...

Mexico adds coronavirus social distancing to its earthquake plan. (2020, April 10). Puerto Vallarta News. https://www.vallartadaily.com/mexico-adds-coronavirus-social-distancing-...

Mexico has an earthquake warning system, what about the U.S.? (2017, September 23). CBS This Morning. https://www.youtube.com/watch?v=oGkad-FLk0w

R. Dallon Adam. (2020, August 11). Open-source earthquake alert system aims to revolutionize seismic monitoring. TechRepublic. https://www.techrepublic.com/article/open-source-earthquake-alert-system...

Rummler, O. (2019, August 27). Trump reallocates $155 million from FEMA disaster relief to fund ICE. Axios. https://www.axios.com/trump-removes-155-million-fema-disaster-relief-fun...

Schachar, N. (2017, October 2). Scientists in Mexico Scramble to Deploy Seismic Sensors. The New York Times. https://www.nytimes.com/2017/10/02/science/mexico-earthquakes-prediction...

ShakeAlert FAQ (Open-File Report). (2018). [Open-File Report]. USGS. https://www.shakealert.org/faq/#current

Sieff, K. (2020). Mexican officials raise Oaxaca earthquake death toll to seven. Washington Post. https://www.washingtonpost.com/world/the_americas/mexican-officials-rais...

Hares, S. (2018, February 6). Quake alerts no substitute for resilient buildings, communities: Mexico scientists. Reuters. https://www.reuters.com/article/us-mexico-quake-science-idUSKBN1FQ2M3

Suárez, E. (2020, June 24). An earthquake hit Mexico and doctors and nurses stayed inside with their patients. AL DÍA News. https://aldianews.com/articles/culture/earthquake-hit-mexico-and-doctors...

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