Week 3 data dive
Connor McNally
2024-09-17
types <- quakes %>% group_by(type) %>% summarize(n_types = n_distinct(type)) %>% arrange(desc(n_types)) %>% pluck("type")
quakes %>% ggplot(aes(x=mag,fill=type)) + geom_histogram(bins = 36) + theme_classic()
The number of earthquakes is so large compared to the number of nuclear explosions and volcanic eruptions within the data that those two groups are barely visible on this chart.
Nuclear explosions are likely so uncommon simply because the are typically a man-made occurence - the four nuclear events in the data were all (likely) nuclear bomb tests - and such events do not happen often.
Volcanic eruptions may be uncommon in the data because volcanic eruptions themselves are relatively uncommon compared to both the number of volcanoes on earth and the number of earthquakes that happen in a year.
magType <- quakes %>% group_by(magType) %>% summarize(n_types = n_distinct(magType)) %>% arrange(desc(n_types)) %>% pluck("magType")
quakes %>% ggplot(aes(x=mag,color=magType,fill=magType)) + geom_histogram(bins = 36) + theme_classic() + labs(fill = "magnitude type", color = "magnitude type")
These magnitude measurement types are explained in the data’s
documentation - I will admit that I don’t quite understand what they
themselves mean, but the documentation suggests that some have ranges of
magnitudes within which they are more effective, and that there is some
order in which these measurements have precedence.
I would like to note that there is no mention of “ml (texnet)” in the documentation - I do not know why this is, but I suspect it is simply another ml measurement.
table(quakes[c("type", "magType")])## magType
## type mb Md ml Ml ml(texnet) ms ms_20 mw mwb mwc
## earthquake 9274 1 60 1 1 3 2 118 721 323
## nuclear explosion 4 0 0 0 0 0 0 0 0 0
## volcanic eruption 0 0 0 0 0 0 1 54 0 0
## magType
## type mwp mwr mww
## earthquake 7 264 9166
## nuclear explosion 0 0 0
## volcanic eruption 0 0 0The nuclear explosions all received an mb magnitude - perhaps this was because of the location of the source of the quakes?
All but one of the volcanic eruptions received a mw magnitude - perhaps the one that didn’t is in a location far enough from points of measurement where obtaining an mw magnitude is infeasible.
table(quakes[c("magSource", "magType")])## magType
## magSource mb Md ml Ml ml(texnet) ms ms_20 mw mwb mwc mwp mwr
## ak 6 0 18 0 0 0 0 65 0 0 0 2
## car 0 0 0 0 0 0 0 0 0 0 0 2
## ci 0 0 0 0 0 0 0 16 0 0 0 0
## csem 0 0 0 0 0 0 0 1 0 0 0 0
## gcmt 0 0 0 0 0 0 0 0 0 313 0 0
## guc 0 0 0 0 0 0 0 0 0 0 0 46
## hv 1 0 9 0 0 0 0 56 0 0 0 0
## iscgem 0 0 0 0 0 0 0 2 0 0 0 0
## ld 0 0 1 0 0 0 0 0 0 0 0 0
## mdd 0 0 0 0 0 0 0 0 0 0 0 1
## nc 0 0 2 0 0 0 0 26 0 0 0 0
## nn 0 0 12 0 0 0 0 0 0 0 0 0
## official 0 0 0 0 0 0 0 1 0 0 0 0
## pgc 0 0 1 0 0 0 0 1 0 0 0 31
## pr 0 1 13 1 0 0 0 2 0 0 7 0
## rsnc 0 0 0 0 0 0 0 0 0 0 0 4
## se 0 0 0 0 0 0 0 1 0 0 0 0
## tx 0 0 2 0 1 0 0 0 0 0 0 0
## ucr 0 0 0 0 0 0 0 0 0 0 0 5
## us 9271 0 1 0 0 3 3 0 721 6 0 172
## us_gcmt 0 0 0 0 0 0 0 0 0 4 0 0
## us_pgc 0 0 0 0 0 0 0 0 0 0 0 1
## uu 0 0 0 0 0 0 0 1 0 0 0 0
## wel 0 0 1 0 0 0 0 0 0 0 0 0
## magType
## magSource mww
## ak 45
## car 0
## ci 0
## csem 0
## gcmt 0
## guc 4
## hv 0
## iscgem 0
## ld 0
## mdd 0
## nc 0
## nn 0
## official 0
## pgc 0
## pr 0
## rsnc 0
## se 0
## tx 0
## ucr 0
## us 9117
## us_gcmt 0
## us_pgc 0
## uu 0
## wel 0There are many potential combinations of magnitude source and magnitude type that do not exist.
One group of note is the aforementioned “ml (texnet)” and all magnitude sources excluding Texas - this is very likely due to TexNet being an earthquake catalogue for the state of Texas.
Another group of note is “Md” and all magnitude sources excluding Puerto Rico - this is likely due to Md being a sort of “last-resort” magnitude measurement, only used when no others are available - though this makes the presence of such a measurement in the data somewhat interesting.
Of the most and least likely combinations, ones of particular note are :
“mww” and US - this is likely because the data was obtained from a US government website, and mww magnitudes are the go-to magnitude for the USGS, if they are available.
“mb” and US - again, this is likely because the data was obtained from a US government website, and a significant portion of the earthquakes in the data had magnitude less than (or equal to) 5.5 - below the point where the methods that take precedence over this one seem to be typically used.
“Ms”/“Ms_20” and US - the only “Ms” measurements in the dataset - documentation suggests that events for which these measurements are made also typically receive Mw magnitudes, so they should be uncommon.
All combinations involving a magnitude source associated with only one datapoint - “csem”, “mdd”, “wel”, and the Center for Earthquake Research and Information (“se”). These are of particular note as all but “se” are not listed in the list of catalogues in the data’s documentation.