The December 18, 2023, M5.9 earthquake in north-central China occurred as a result of reverse faulting at shallow depth. The earthquake occurred on either a north-striking, steeply dipping, reverse fault or a south-southeast striking, shallowing-dipping, reverse fault. The region where the December 18th earthquake occurred is an intraplate (i.e., not at a plate boundary) region located on the northern margin of the Tibetan Plateau. The Tibetan Plateau is a high topographic region north of the Himalaya Mountains that developed in response to ongoing collision between the India and Eurasia plates.
The Tibetan Plateau is tectonically active, and earthquakes are common throughout the region. Within 250 kilometers of today's event, 23 M5.5 and larger earthquakes have occurred since 1900. The largest of these is a M7.7 earthquake in May 1927, to the north that resulted in roughly 40,000 fatalities. The 1927 earthquake resulted in extreme damage in the Gulan-Wuwei area and resulted in damaging landslides. In April 1990, a M6.5 earthquake, immediately preceded by a M6.3 foreshock and followed by a M6.3 aftershock, led to at least 126 fatalities and extensive shaking damage and landslides. Earthquake-related losses in China are common, even for moderate magnitude earthquakes, owing to the proximity of large population centers to shaking, the prevalence of structures that are vulnerable to earthquake shaking, and the occurrence of landslides in steep topography.
The "M 5.9" indicates the magnitude of the earthquake on the Richter scale, measuring the energy released by the earthquake. A magnitude of 5.9 is considered moderate and can cause damage, especially to poorly constructed buildings.
This describes the epicenter of the earthquake, which was located 37 kilometers West-Northwest of Linxia Chengguanzhen, a city in China. The location helps in identifying the areas potentially affected by the earthquake and in coordinating emergency response efforts.
An earthquake of this magnitude can lead to structural damage in buildings, especially those not designed to withstand seismic activity. There could also be disruptions to utilities and services, landslides, and aftershocks that may further affect the stability of the region.
Residents should check for injuries and ensure their safety first, avoid damaged buildings, be aware of potential aftershocks, and follow updates and instructions from local authorities regarding evacuation or other safety measures.
Earthquakes are monitored by seismological centers around the world using networks of seismometers that detect and record the vibrations caused by seismic waves. The data is analyzed to determine the location, depth, and magnitude of the earthquake. This information is then reported to authorities, media, and the public to provide warnings and updates.