In California, the San Andreas Fault is known for earthquakes. Researchers observe an area very closely. There is a threat of a strong earthquake here every day.
Parkfield – It is a small, remote town in the “Golden State” of California (USA). But Parkfield is special. The city is located on the earthquake-infamous San Andreas Fault. Scientists now suspect that the next earthquake is imminent.
Quake on the San Andreas Fault |
Date |
|---|---|
Parkfield earthquake |
June 28, 1966 |
Parkfield earthquake |
September 28, 2004 |
possible next Parkfield earthquake: |
2024 |
Source: USGS |
Severe earthquakes on the San Andreas Fault occur in a specific cycle
Major earthquakes (magnitude 6 or greater) occur in the Parkfield region approximately every 22 years. The last one occurred on September 28, 2004 - albeit a little late, namely 38 years after the quake in 1966. According to the statistics in Parkfield, the next major earthquake is imminent.
Scientists wanted to find out when this actually takes place. To improve earthquake prediction, a research team examined
the section along the fault line as part of the study published in the journal
Frontiers in Earth Science
. They noticed a pattern that could indicate the next earthquake.
Before the last earthquake in 2004, the attenuation of low-frequency seismic waves increased while the attenuation of high-frequency waves decreased, according to the study. This happened within a period of six weeks before the quake. According to research results, a similar process is taking place at the moment.
“We cannot yet find any evidence that the Parkfield asperity has reached its critical state,” the authors write in their study. However, the research team believes they have discovered unique seismic activity that points to a strong earthquake later this year. Even if the epicenter of the next quake could be somewhere else.
Earthquake risk in California – Researchers find patterns on the fault line in Parkfield
“I'm waiting for the next earthquake,” said lead author of the study, Luca Malagnini, director of the Italian Istituto Nazionale di Geofisca e Vulcanologia (INGV) to the knowledge portal
Live Science
. “And then we will look back.” The earthquake expert therefore does not want to try to predict the next earthquake to the exact day. But he and his team hope to identify signals after an earthquake that people should pay attention to in the future.
Because of their remote location, these earthquakes rarely threatened human life or property, Malagnini continued. Unlike the dreaded “The Big One,” which studies show is likely to hit Southern California in the next 30 years with a magnitude of 6.7, according to the USGS earthquake monitoring station.
According to the study, Parkfield was chosen “because of its very simple geometry and behavior.” North of Parkfield, the San Andreas Fault moves freely. South of Parkfield the fault is blocked. However, the two tectonic plates are shifting against each other at a constant rate of 3.6 centimeters per year.
There are also earthquake hotspots in Europe: in Turkey the Anatolian and Arabian plates are colliding. “Istanbul will be the target of the next earthquake,” researchers fear. The question is not whether the catastrophe will happen, but when.
(ml)