The marigraph of Marseille

Collection title

Journal de bord

ID

INA00074

Source

INA (FR)

First broadcast date

11/25/1981

Production year

1981

Abstract

The ‘marigraph’ (tide gauge) was built in 1884 on the Corniche of Marseille to record tides and sea level in the Mediterranean. 0 determines its setting elevations for the entire Mediterranean region, which was very useful for the digging of the Suez Canal. Interview with Mr. Blancart, geographer and head of the tide gauge. The sea level has risen by 20cm since the beginning of the century. He gives two hypotheses: the melting ice of the poles or the tectonics of the Earth crust.

Type

video

Production companies

• France 3 Marseille - Own production

Broadcaster

FTV - F3

Audiovisual form

Magazine

Primary theme

Physics and mathematics

Credits / Cast

• Paolini Gérard - Journalist

Period of events

• From 1850 to 1900

Map locations

• France - South East - Marseille

Original language

French

Media running time

2m19

Additional information

Context

 

This news item gives us the chance to remember the important part played by the tide gauge at Marseille, measuring the altitude in France and in Europe from the level of the sea – but to be able to define that zero level we have first to know (or decide) what the level of the sea is. Because of the very small tides in the Mediterranean the sea level at Marseille was chosen as the standard in the 19th century. The first level had been measured in 1860 by Bourdaloue at Fort St Jean at the entrance to Marseille's harbour. A new system, more reliable, was built in 1884 on the Corniche in the bay of Calvo, just past the bridge of Fausse-Monnaie. The mechanism has remained in its orginal state and gives the zero level for France, used mainly by the Institut Géographique National for map-making. But today the level of the seas is measured with much greater accuracy by satellites using radar altimetry.

This report also gives a tide gauge technician the chance to talk about the sea and ocean levels found during the 20th century and to risk a few explanatory theories. We know that this issue is linked to global warming, and is now of course the object of many international scientific studies.