Mw 7.4 Earthquake Rattles Eastern Taiwan

CoreLogic estimated insurable losses in Taiwan to be between $5.0 – $8.0 billion

On April 3, 2024, multiple strong earthquakes shook eastern Taiwan causing damage and disruption. The largest quake — with a magnitude (Mw) of 7.4 and a depth of 34.8 km (21.6 miles), according to the United States Geological Survey (USGS) — occurred at 7:58 a.m. local time (11:58 p.m. UTC on April 2). This was followed by nearly 30 strong aftershocks, including a Mw 6.4 earthquake 13 minutes later.

The epicenter was located about 22.0 km (13.7 miles) south-southeast of the city of Hualien in Hualien County on Taiwan’s east coast. The shaking lasted for about a minute and was felt across the island as well as in some parts of mainland China and Japan. The capital city of Taipei is 137.2 km (85.3 miles) away from the epicenter.

Neighboring countries such as Japan and mainland China did not report any tsunamis. The Japan Meteorological Agency detected a tsunami wave of about 1 foot on the coast of Yonaguni Island, east of Taiwan. However, the agency reported no major damage from the waves.

Taiwan leads the globe in semiconductor chip manufacturing with facilities operating along the west coast from Taipei to Tainan. A major impact to plant facilities or shipping networks could have a significant global impact since technology companies use the chips produced in Taiwanese facilities in a range of products from computers to vehicles. Fortunately, early reports from Taiwan indicate little to no damage or disruption to chip manufacturing plant operations.

Modeled Loss From the Mw 7.4 Taiwan Earthquake

CoreLogic estimated that insurable losses from the April 3 Mw 7.4 earthquake will be between $5.0 and $8.0 billion (160.2 – 256.2 billion TWD).

The losses include ground shaking and fire-following damage to only residential, commercial, industrial, and agricultural properties in Taiwan. They do not include any damage to government buildings and transportation infrastructure such as bridges or roads. Demand surge is included.

The insurable losses represent ground up damage and do not consider the application of policy deductibles or limits. The estimate does not exclude losses ceded to the Taiwan Residential Earthquake Insurance Fund.

Risk Quantification and Engineering® (RQE) model users can download proxy events from the stochastic CoreLogic Taiwan Earthquake Model on the Client Resource Center (CRC).

Strong Seismic Codes May Mitigate Some Loss

Hualien County will likely see the most damage from the Mw 7.4 earthquake. Fortunately, Taipei’s strong building codes for modern buildings mitigated major damages.

Taiwan has a long history of development, implementation, and enforcement of seismic codes. However, there remains a mix of modern, well-designed buildings and older, unreinforced  masonry and non-ductile concrete buildings.

Taiwan introduced the first seismic code in 1974. This code was based on the U.S. Uniform Building Code and was later revised in 1982 to incorporate the importance factors for various building occupancy classes. A major update in 1997 included the dynamic analysis procedures using the response spectrum method; a change in seismic zoning and the associated zoning factor; and the adjustment of force reduction factor. The most modern version of the Taiwan seismic code was released in 2005.

Taiwan residential, commercial, industrial, and agricultural construction practices primarily rely on reinforced concrete for building materials. Unreinforced masonry is also common in residential construction, though to a lesser degree than reinforced concrete. Commercial and industrial properties rely on steel construction as the next most common building material. Agricultural properties can use a range of different materials, including both reinforced and unreinforced masonry and steel.

Earthquakes Are Common in Taiwan

A reverse thrusting mechanism along the subduction zone boundary of the Eurasia Plate and Philippine Plate characterizes this earthquake sequence. However, given the shallow depth of the earthquake, it is likely that the source originated within the Eurasia plate above the subduction zone.

Taiwan has a long history of disastrous earthquakes. In the past 50 years, there have been six Mw 7.0 or stronger earthquakes that have struck within 250 km of the April 2024 Mw 7.4 event. The most recent catastrophic earthquake was the Mw 7.6 Chi-Chi Earthquake in 1999. This earthquake caused approximately 2,400 deaths and 11,000 injuries. The earthquake also damaged over 100,000 buildings — destroying approximately 52,000 buildings and severely damaging another 54,000 — at an estimated cost of $14.1 billion, according to the International Disaster Database, EM-DAT as of 2012.

Initial monetary impact estimates from the April 3 Mw 7.4 earthquake and subsequent aftershocks are not expected to be as devastating as the Chi-Chi Earthquake.

Reports from Taiwan indicate some severe damage and travel disruptions in eastern Taiwan, especially in Hualien County. Some of the most impacted buildings were the Hualien Hospital, the Hualien Cultural Center, and the Marshal Hotel. Disruption to the power, water, and communication networks, as well as the transportation system have been reported. Officials temporarily closed the Hualien Airport and the Taiwan Railway, and landslides damaged or blocked roads and bridges.

CoreLogic Hazard HQ Command Central™ will continue to analyze the damage left in the aftermath of the Mw 7.4 earthquake in Taiwan. Additional information may be provided if new data is found.

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