Understanding Earthquake Warnings: The Need for Social Insight
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Chapter 1: The Challenge of Earthquake Alerts
The issue of when to issue earthquake warnings is a complex one. Recent seismic activity in Southern California left many residents in Los Angeles feeling frustrated. Despite experiencing tremors from earthquakes that were over 100 miles away in Ridgecrest, many received no alerts via their ShakeAlertLA apps. The app functioned as intended, however, only alerting users once the shaking was expected to reach a Modified Mercalli Intensity (MMI) of 4—an intensity that typically causes minor damage, like items falling from shelves.
Following the public outcry, officials acted quickly. The very next day, they announced a reduction in the alert threshold to MMI 3, a level generally felt by individuals but rarely causing damage, akin to the sensation of a large truck passing by. In October, California's Governor Gavin Newsom introduced a statewide earthquake alert system, allowing residents to receive notifications through the MyShake app and other wireless emergency alerts, similar to Amber Alerts or flash flood warnings.
However, geologists express concerns that these alert systems were deployed without thorough consideration of how the public would utilize them. Elizabeth Cochran, a research geophysicist with the USGS, emphasized, "I don’t believe there’s been a sufficient introduction to this system."
In a recent publication in Science, Cochran advocates for additional research to determine the optimal threshold for these warnings. While the public is generally receptive to receiving alerts, there remains a lack of understanding regarding how individuals react—evidence even suggests that these alerts can sometimes yield negative outcomes.
Section 1.1: Mechanics of Early Earthquake Warnings
Early earthquake notifications are triggered when seismic stations detect movement along nearby faults. Sensors capture the initial waves of an earthquake, allowing automated systems to predict how far and how intensely the shaking will spread. This process has a very brief window—about two seconds—to issue an alert, which is sent out via local cell towers or through applications.
If an earthquake occurs directly beneath a city, immediate alerts are impossible. However, for individuals located further away, these systems can provide crucial seconds—ranging from a few to several—to seek safety.
Although these predictions are not flawless, as substantial quakes may take over a minute to reach their peak intensity, alerts are typically issued for a variety of shaking scenarios to account for potential discrepancies.
Subsection 1.1.1: Human Reactions to Alerts
Cochran has expressed concern regarding the reactions of individuals in Mexico City following an earthquake warning. After the devastating 2017 Puebla earthquake that resulted in over 300 fatalities, residents received early warnings of subsequent tremors. Unfortunately, two individuals succumbed to heart attacks due to panic, and another jumped from a window—despite the actual earthquake being quite minor and largely unnoticed by the general population.
Such reactions highlight the potential dangers of frequent alerts. If California residents continually receive notifications, they may become desensitized, dismissing warnings as trivial. Conversely, an alert could provoke panic in a driver, leading to accidents. While these scenarios are speculative, Cochran points out a critical gap in our understanding of public response to these notifications.
Diego Melgar, a seismologist at the University of Oregon, concurs, stating, "The technological advancements in earthquake early warnings have progressed rapidly, but we must also delve deeper into understanding how the public responds to these alerts."
Section 1.2: Tailoring Alerts for Better Understanding
In addition to determining the appropriate intensity level for alerts, seismologists must also figure out the best methods for communicating these warnings. Cochran raises concerns that alerts might inadvertently lead individuals to believe they have sufficient time to evacuate buildings, rather than seeking immediate shelter. "In California, that’s not the recommended course of action," she notes. Past incidents have shown that those who attempt to leave buildings often suffer injuries.
Now, the responsibility falls to social scientists to discern the most effective ways to disseminate earthquake warnings. Cochran points out, "The primary unanswered questions reside within the social science domain: How do people prefer to utilize these alerts? How do they respond?" Gaining insights into these areas will allow us to better refine the messages we convey to the public.
Chapter 2: The Importance of Social Science in Earthquake Alerts
This video discusses the significance of earthquake safety and warning systems, highlighting best practices for preparedness.
In this video, GEO GIRL explores the causes of earthquakes and the challenges associated with predicting them, emphasizing the need for ongoing research.