Isochrone maps are not limited to trains, planes, cars and bikes, they are versatile and can describe time relations of various subjects.
Map of estimated tsunami wave isochrone lines in hours after a hypothetical 9.2 magnitude earthquake (source NOAA).
Just like any train travel isochrone map here you can see that it takes 14 hours for a tsunami wave to reach Hawaii and New Zealand, 16 to Australia and 18 to Alaska. It would take 22 hours for a tsunami wave to reach Japan caused by a quake in Chile. The medium (water) the wave travels through differs and in this map one can see that underwater mountains and trenches as well as Pacific islands form barriers of a tsunami wave.
Speaking of Japan and of a more pleasant kind of isochrone map. Every year isochrone maps are drawn of the cherry blossom forecast in Japan, as wonderfully described at the Tokyo Cycling Blog. (We have come full circle to Galton’s weather map.)
Cherry bloom forecast map for 2014 by Japanese weather forecast company, Weather Map.
The cherry blossom map shows with isochrone lines the dates until when the cherry blossoms will bloom, starting with 20th of March in Kyushu to the 10th of May in Hokkaido. But isochrone maps for flowers are not only reserved for Japanese. Below a bloom forecast map of Germany and neighbouring areas with apple blossoms.
Frühlingseinzug, Anfang der Apfelblüte – Lange-Diercke – Sächsischer Schulatlas published around 1930 (found here)
This map shows when you can expect to enjoy apple blossoms in your garden, conveniently titled “Springtime Begins”. Along the upper Rhine and by Budapest already from 22nd to 28th of April up until 20th to 26th of May or later in Copenhagen and in the mountains.
Another way to tell if spring has begun in a mild humid climate is when birds return from their winter grounds in the South (or North depending where you live). The map below shows when you can expect to see the Ruby-throated Hummingbird in the East of North America, isochrone lines split the seasonal migration of these birds into 15 day categories.
Ruby-throated Hummingbird Archilochus colubris by eNature