Lake Suigetsu has the world’s longest varves
(45m long piled up for 70,000 years!)

Research Results

3 What is IntCal?

Radiocarbon (¹⁴Ｃ) dating is the most widely used method in the world for dating time to about 50,000 years ago. However, dating based on the amount of ¹⁴Ｃ remaining is not always accurate and requires a 'conversion table', called a calibration model, to convert the measurements into true values.

The "conversion table" should not vary from one researcher to another, but should be standardized according to a global agreement among the scientific communities. The most widely used calibration model in the world today is called IntCal, which was first proposed in 1998 and has been updated in 2004, 2009, 2013 and 2020.

IntCal is the international standard "measure" that gives definition to geological time, functioning in the same way as the prototype metre or the Greenwich Observatory. Because of its outstanding quali-ty, the data from the Lake Suigetsu Varves was adopted in its entirety for the 2013 edition of IntCal (IntCal13), regarded as a major turning point in the history of IntCal.

Because of IntCal's principle of avoiding over-reliance on data from only one location, IntCal13 also combines data from not only Lake Suigetsu but also other locations. However, it is clear that the Lake Suigetsu Varves provides by far the most reliable data in the IntCal13 components in terms of the number of data used, the "determinacy" of the calibrated ages, and the "purity" of the data in that it did not have to take into account old carbon from deep sea water or limestone.

In August 2020, IntCal was updated for the first time in seven years (IntCal20).

The updated IntCal 20 includes about 250 new stalactite (stalagmite) data from China's Hulu Cave as well as about 500 pieces data from Lake Suigetsu, carried over from IntCal 13, making Lake Suigetsu and the Hulu Cave the two greatest sources of data.

Instructional video of IntCal20 (YouTube)

Research Results

Page Top

Location

122-12-1 Torihama, Wakasa-cho, Mikatakaminaka-gun, Fukui Prefecture 919-1331, JAPAN
inside Jomon Roman Park (adjacent to Wakasa Mikata Jomon Museum)

TEL

+81-770-45-0456

FAX

+81-770-45-3680

MAIL

varve-museum@pref.fukui.lg.jp

Opening hours

9:00 to 17:00(Entrance gate closes at 16:30.)

Closed days

every Tuesday & Year-end and New Year holidays (12/29 to 1/2)

If a national holiday falls on a Tuesday, the following day becomes a closed day.
No closed days during the Golden Week holidays and the summer holidays
We are subject to temporary closure due to maintenance of our facility, etc.

Admission fee

Adults: 500 yen / Students (aged 6 to 18): 200 yen

Combo ticket covering Wakasa Mikata Jomon Museum is 30 percent off.
A group over 20 people is 20 percent off.

Permanent exhibition	Individual	Ordinary admission ticket	Adults	500 yen
		Ordinary admission ticket	Students (aged 6 to 18)	200 yen
		Combo ticket covering Wakasa Mikata Jomon Museum	Adults	700 yen
		Combo ticket covering Wakasa Mikata Jomon Museum	Students (aged 6 to 18)	280 yen
	Group	Ordinary admission ticket	Adults	400 yen per person
		Ordinary admission ticket	Students (aged 6 to 18)	160 yen per person
		Combo ticket covering Wakasa Mikata Jomon Museum	Adults	560 yen per person
		Combo ticket covering Wakasa Mikata Jomon Museum	Students (aged 6 to 18)	220 yen per person

Admission is free for visitors over 70 and under 6.　People over 70　are required to show their ID cards verifying their age such as health insurance card, etc.
Group discount is applied to a group of over 20 people except those eligible for free entrance.
Admission is free for the students in Fukui Prefecture aged 6 to 18, including students in special support education schools and people in charge of each student group. (Prior reservation is required.)
No admission fee is required for the visitors who produce their physical disability certificate or certificate for livelihood assistance or education assistance at the information desk.
No admission fee is required for all the visitors on Family Day (every 3rd Sunday) and Hometown Day (February 7).

Our facility

70-space parking area (shared with Wakasa Mikata Jomon Museum)
3 wheelchair & 2 stroller
Multipurpose toilet & bed for diaper change
Elevator
In case of using a wheelchair, please tell us at the information desk. Our staff will assist the visitor in wheelchair.

Requests to the visitors

Please refrain from eating and drinking in the museum.
Smoking is prohibited in the museum.
Entry with your pets into the museum is prohibited except with helper dogs.
Please refrain from any nuisance to other visitors such as making a noise in a loud voice, running around in the exhibition rooms or down the hall, etc.

Explanation of exhibits

Up to three guides are permanently stationed in the museum, who explain our exhibits to the visitors. Should you have any questions, please feel free to ask them.
As for our guidance service, priority is basically given to the visitors with advanced reservation. When we have many visitors, however, please note that there are cases where we can’t provide appropriate guidance service.

Reservation

Prior reservation is recommended as much as possible for the group visitors. Without reservation, you may not be guided smoothly.
Please feel free to contact us by phone, fax and email for your reservation.
In case of visiting us in a group of over fifty people, we recommend that the entire group be divided into more than two smaller groups and visit us and Jomon Museum adjacent to our museum alternately. Over fifty visitors at a time may make our guides unable to provide appropriate guidance service. In that case, please consult with us in advance.