earth science

Mexican Seismic Alert System

Mexican Seismic Alert System is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Mexican Seismic Alert System rather than just read about it. In short: The Mexican Seismic Alert System (Spanish: Sistema de Alerta Sísmica Mexicano or SASMEX) is the earthquake warning system covering portions of central and southern Mexico. It currently provides up to 60 seconds' warning of earthquakes to Mexico City, Acapulco, Chilpancingo, Morelia, Puebla, Oaxaca, Guadalajara, Colima and Toluca.

Key takeaways

Mexican Seismic Alert System belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Mexican Seismic Alert System to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Mexican Seismic Alert System from memory before moving on to harder problems.

Reference excerpt

The Mexican Seismic Alert System (Spanish: Sistema de Alerta Sísmica Mexicano or SASMEX) is the earthquake warning system covering portions of central and southern Mexico. It currently provides up to 60 seconds' warning of earthquakes to Mexico City, Acapulco, Chilpancingo, Morelia, Puebla, Oaxaca, Guadalajara, Colima and Toluca. SASMEX is administered by a non-profit civil association, the Center for Seismic Instrumentation and Registry (Spanish: Centro de Instrumentación y Registro Sísmico, A. C. or CIRES). The SASMEX sensor network serving Mexico City has been regarded as the first earthquake early warning system issuing alerts available to the public. SASMEX supplies regular information of all kinds, including reports of earthquakes of all magnitudes, and drills, via X, under the name AlertaSísmica SASMEX. All earthquakes are reported as #TenemosSismo (we have an earthquake); warnings of serious ones are delivered as #AlertaSismica (earthquake alert).

History The 1985 Mexico City earthquake prompted a national rethink of earthquake and emergency preparedness measures. The government of Mexico City sponsored the placement of accelerometers throughout the city in 1987, allowing data to be obtained on ground movements in the area. With the support of the local government, CIRES developed Mexico City's earthquake alert system, which began operating with 12 sensors in 1991 and has been publicly available since 1993. CIRES was tapped to develop a similar system for the state of Oaxaca after it was struck by a Mw 7.4 earthquake in 1999. Beginning in 2000, CIRES and the state government developed an early warning system for Oaxaca, which entered into service in 2003. The two formerly separate earthquake warning systems were combined in 2005 to form SASMEX.

Current sensors The SASMEX system contains 97 sensors, primarily along the coast from Puerto Vallarta south, in the mountains of the state of Guerrero, and in northern Puebla and across most of Oaxaca. An expansion to the network of 28 sensors, currently in development, would add monitoring capabilities in Oaxaca's Isthmus region, inland portions of Veracruz, and the western two-thirds of Chiapas. Historically, CIRES has been able to provide 60 seconds of warning time to Mexico City in the event of an earthquake along the southern coast, and as many as 30 seconds to the city of Oaxaca if an earthquake occurs near the coast of that state, with shorter lead times for earthquakes centered closer to the city.

Transmission of alerts CIRES transmits earthquake early warning alerts through a network of VHF stations similar to the NOAA Weather Radio service in the United States, including use of Specific Area Message Encoding, but with faster lead times in order to issue more timely warnings within two seconds or less. CIRES offers alert systems for buildings and personal use, which also come pre-installed with the official warning sound used for earthquake alerts in Mexico. On its network of transmitters, CIRES issues required weekly tests every three hours to ensure receivers are connected to its network, as well as earthquake warnings when necessary. More than 90,000 users in Mexico City, including almost all public schools, have receivers. The Mexico City Metro additionally receives SASMEX alerts, although not for public dissemination but instead to stop trains or delay departures as necessary. CIRES alerts are also transmitted by major broadcasters in Mexico City, Toluca, Acapulco, Chilpancingo and Oaxaca and, as of 2015, through Mexico City's municipal loudspeaker network with more than 8,200 speakers installed. During the 2012 Guerrero–Oaxaca earthquake, the SASMEX system (at that time not fully unified) provided 25 seconds of warning to Oaxaca, 45 seconds to Chilpancingo and Acapulco, and 80 seconds to Mexico City. The system was also effective during the 2017 Chiapas earthquake. SASMEX's warning was activated a few seconds after the shaking was felt in Mexico City for the 19 September 2017 earthquake, rendering it ineffective for the only seismic event that has caused loss of life in Mexico City since the 1985 Mexico City earthquake. Some people may have taken the alert for a continuation of an earthquake drill held three hours before. Six stations reported, and alerts 12 to 48 seconds before the shock were also provided to Oaxaca, Acapulco, Chilpancingo, Guadalajara, Colima and Puebla (this has not been verified by an external agency).

References

External links CIRES website [1] [2]

Illustrations

Worked examples

Example 1 — a first encounter with Mexican Seismic Alert System

Start with the simplest possible case. Write down what Mexican Seismic Alert System claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Mexican Seismic Alert System before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Mexican Seismic Alert System ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Mexican Seismic Alert System

In research: Mexican Seismic Alert System appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Mexican Seismic Alert System in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Mexican Seismic Alert System is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1991 establishments in Mexico, Earthquake early warning systems, Earthquakes in Mexico, so understanding it makes those chapters shorter.
In everyday life: Look for Mexican Seismic Alert System outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Mexican Seismic Alert System” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Mexican Seismic Alert System in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mexican Seismic Alert System means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Mexican Seismic Alert System out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mexican Seismic Alert System in simple terms?

Why does Mexican Seismic Alert System matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Mexican Seismic Alert System?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Mexican Seismic Alert System.