Protecting Important Cultural Properties and Cultural Heritage: An Introduction to Seismic Isolation Display Cases

A Recent Series of Large Earthquakes

Recent years have seen large earthquakes of seismic intensity 7 and greater bring devastation to various parts of Japan, from the most recent Noto earthquake that struck on January 1, 2024, to the Hokkaido Eastern Iburi earthquake in 2018, the 2016 Kumamoto earthquakes, and the Great East Japan Earthquake of 2011. Each disaster brings reports of damage to display cases and cultural heritage items at museums, making it imperative that countermeasures be taken to protect these irreplaceable objects from future earthquakes.

Seismic Isolation Optimized to Protect Cultural Properties from Earthquakes

There are three ways to defend against earthquakes: earthquake-proofing, seismic damping, and seismic isolation. Earthquake-proofing involves an object withstanding tremors. It assumes that the structure of the object can withstand the force of seismic tremors without being damaged. Seismic damping reduces the energy of earthquake tremors. These structures absorb seismic tremors using built-in seismic damping materials such as weights. Finally, seismic isolation deflects earthquake tremors. Installing a seismic isolation system between a structure and the ground prevents the direct transfer of energy from seismic tremors to the structure itself.

Museum Display Cases

Most people have likely seen a number of different display cases before in museums. These cases must not only give visitors a clear, appealing, and impactful view of the objects arrayed inside, but also protect and preserve these objects. Particularly in Japan, where earthquakes are common, display cases that incorporate seismic isolation to protect and preserve cultural properties are attracting attention.

Creating a Seismic Isolation Table Using Lessons Learned from Large Earthquakes

Countless times in the past, the occurrence of an earthquake has prompted museums to discuss what measures to take against them. In the midst of this, THK hit on the idea for a seismic isolation table that could minimize how much a display case might shake during an earthquake and thus reduce damage to the case itself and the objects inside while also preventing human injury caused by a case or a display object falling over or the glass of a case shattering. Using this idea as a springboard, we developed the Seismic Isolation Table Model VIT to fit standard sizes of the freestanding rectangular display cases often seen in museums.

Five Features of the Seismic Isolation Table Model VIT

1. An expansive lineup with a standard surface shape

The VIT lineup is compatible with a variety of display cases, allowing for optimal product selection. This expedites discussions about installation and supports a smoother installation process overall.
Shape: The square surface allows the VIT to be used as a seismic isolation system for various kinds of loaded objects.
Product lineup: These seismic isolation devices, primarily intended for freestanding rectangular display cases, come in four different surface sizes (from 600 mm to 1,200 mm wide).

2. Standardized seismic isolation performance

We provide the results of response analysis performed with standard seismic waveforms so that the effectiveness of our seismic isolation can be verified without complicated calculations or evaluations. This allows customers to select the product they want with peace of mind.
Performance verification method: The range for the mass of the loaded object is set for each phase of the response analysis, which is performed using three standard waves (from the 1940 El Centro, 1952 Taft, and 1968 Hachinohe earthquakes) (50 kine) and the JMA Kobe wave. This makes it easy to confirm the performance of the VIT.

3. Thin design

The VIT can be installed without detracting from the design of a display case's exterior. It also allows for effective use of limited display space.
Design: The height of the VIT, including its two-axis seismic isolation unit, the finished steel plate, and the top frame, comes in at just 96 mm.

4. Maintenance-free operation

Dust seals on the LM Guide units used by the Model VIT eliminate the need for daily maintenance, which helps to reduce the cost of managing the equipment.
Specifications: LM Guide units with dust seals provide linear motion for this maintenance-free product. The specific LM Guide used here is the Utility Slide Model UGR.

5. A wide array of options

With add-ons like a cosmetic baseboard to go around it and a base frame to simplify moving it, the Model VIT can be customized to suit a variety of needs. These options provide seismic isolation tailor-made for different installation locations and methods of use.
Options: We offer a slide-on cosmetic baseboard to go around the seismic isolation system, a base frame designed to help move loaded objects, and other optional add-ons.

Use Cases for the Seismic Isolation Table Model VIT and the Rectangular Seismic Isolation Table

The Ohara Museum of Art (Using the Seismic Isolation Table Model VIT)

Located in Kurashiki, Okayama Prefecture, this private art museum is known as the first in Japan to center its collection around Western art. Though mainly known for its many famous Western paintings, its works of Japanese and Eastern art make it near and dear to many as a place for appreciating a diversity of styles. We are honored that the museum uses our Seismic Isolation Table Model VIT to protect its many invaluable pieces from earthquakes.

The National Crafts Museum (Using Our Rectangular Seismic Isolation Table)

Located in Kanazawa, Ishikawa Prefecture, this museum preserves and displays works of traditional and contemporary Japanese craftsmanship. Traditional crafts continue to thrive in Kanazawa. In the midst of the city's rich culture and history, the museum gives visitors a look at the allure of Japanese handicrafts. We are honored that the museum uses our rectangular seismic isolation tables* to protect its many invaluable pieces from earthquakes. We've even received words of thanks from the museum’s director, Mr. Karasawa, who recalls that “The 2024 Noto earthquake caused extensive damage at a number of cultural centers, but here, not a single piece protected by seismic isolation suffered the same. This is all thanks to these display cases and their seismic isolation systems, and I am immensely grateful for them.”

Installing and Using the Seismic Isolation Table Model VIT

Installing the Seismic Isolation Table Model VIT couldn't be easier! The first step is to get in touch with THK. We’ll ask about the type of cultural property you want to protect and the size and placement of your display cases so that we can propose the best Seismic Isolation Table Model VIT for your situation. 

Installation Process

1. Consultation/Inquiry
Start by reaching out to us by phone or using our inquiry form. Our expert staff are ready to help.  

Preserving Important Cultural Properties for Generations to Come

Cultural properties are valuable pieces of our heritage that reflect our culture and history, and we have a responsibility to pass them on to future generations. In earthquake-prone Japan, this means that it is crucial that we effectively protect these precious assets from earthquakes using seismic isolation. Beyond this, as seismic isolation systems are increasingly stipulated as a condition for borrowing objects to display in special exhibitions, these systems are only becoming more important to the way that cultural properties are used.