From Haicheng to Parkfield: The Evolution of Earthquake Prediction in Science

The era of scientific earthquake prediction began around the mid- to late 1970s, catalyzed by events in China. An extraordinary case took place during winter 1975 when Hcheng city, located in northeastern Liaoning Province with a population of about one million people, was evacuated based on observations and reports from scientists as well as local observers across a vast region experiencing unusual phenomena.

Changes in land elevation and water levels were reported while peculiar animal behaviors sparked concerns that might precede an earthquake. A rise in seismic activity preceding the mn event a so-called foreshock sequence rsed low-level alarms and later warranted evacuation warnings due to increased foreshock activity. The magnitude 7.3 earthquake struck Hcheng days later on February 4, resulting in physical injuries and fatalities affecting only a minor portion of the population. An estimated death toll was approximately 2,041 people with an additional injury count totaling 27,538. It's speculated that without such a prediction and evacuation, fatalities and injuries might have surpassed 150,000.

This success story did not deter scientific ambitions but rather ignited them. However, the hope for reliable earthquake prediction was short-lived when on July 28, 1976, an even more devastating magnitude 7.6 earthquake struck Tangshan city - a thriving industrial hub with approximately one million inhabitants that showed no signs of precursors similar to those in Hcheng.

The scientific community's interest in depable methods for earthquake prediction grew significantly post the 1975 event. In response, Congress established the National Earthquake Hazards Reduction Program NEHRP in 1977. The program currently involves four agencies including the US Geological Survey USGS, National Science Foundation NSF, Federal Emergency Management Agency FEMA, and National Institute for Standards and Technology NIST. It focuses on mitigating earthquake risks through research across three fields: earth science, engineering, and social sciences.

At its peak, earthquake prediction studies comprised about 20 of the USGS-funded part of the program. Currently, NEHRP's emphasis is directed towards the Parkfield Earthquake Prediction Experiment which is a key initiative in the region.

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Introduction

Geological Setting

Historical Earthquakes

Scientific Progress

Prediction eavors

Hcheng Incident and its Aftermaths

Foundations of Scientific Justification

Policy and Risk Management Levels

Parkfield Observatory at Depth

Seismic Simulation Laboratory

Networks for Data Collection Analysis

Accessing Data

Parkfield Earthquake Observatory in Depth

Activity Level Analysis

Home

Earthquakes

Hazards Mitigation

Research Focus

Monitoring Systems

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