Load a table of earthquakes around Japan as a pandas.DataFrame.
Data is from the NOAA NGDC database. This is the
@tut_quakes.ngdcdataset used in the GMT tutorials.
The data are downloaded to a cache directory (usually
~/.gmt/cache) the first time you invoke this function. Afterwards, it will load the data from the cache. So you’ll need an internet connection the first time around.
data (pandas.DataFrame) – The data table. Columns are year, month, day, latitude, longitude, depth (in km), and magnitude of the earthquakes.