• Aim: create and display an interactive map of recent earthquakes around Italy and the surrounding seas
• Data taken from the Italian National Institute of Geophysics and Volcanology

• Data available at the INGV page is taken using the INGV webservices and downloaded as a text file to a local file.

if(!file.exists('earthquakes.txt')) {
  download.file('http://webservices.ingv.it/fdsnws/event/1/query?starttime=2017-10-09T00%3A00%3A00&endtime=2017-10-16T23%3A59%3A59&minmag=2&maxmag=10&mindepth=-10&maxdepth=1000&minlat=-90&maxlat=90&minlon=-180&maxlon=180&minversion=100&orderby=time-asc&format=text&limit=10000', destfile = 'earthquakes.txt', method = "curl")
}

• The downloaded file is a simple text with header and columns delimited by '|'.

df <- read.csv('earthquakes.txt', header=TRUE, sep="|")

str(df)

## 'data.frame':    63 obs. of  13 variables:
##  $ X.EventID        : int  17280571 17285641 17286531 17286991 17288681 17289441 17290341 17290871 17292271 17293271 ...
##  $ Time             : Factor w/ 63 levels "2017-10-09T05:22:18.970000",..: 1 2 3 4 5 6 7 8 9 10 ...
##  $ Latitude         : num  43 42.7 42.8 38.8 42.8 ...
##  $ Longitude        : num  13.1 13.1 13.2 15.6 13.2 ...
##  $ Depth.Km         : num  9.1 10.4 10.3 88.4 10.3 118 11.9 19.5 12.3 10.5 ...
##  $ Author           : Factor w/ 3 levels "SURVEY-INGV",..: 1 1 1 1 1 1 1 2 1 1 ...
##  $ Catalog          : logi  NA NA NA NA NA NA ...
##  $ Contributor      : logi  NA NA NA NA NA NA ...
##  $ ContributorID    : logi  NA NA NA NA NA NA ...
##  $ MagType          : Factor w/ 3 levels "Md","ML","Mwp": 2 2 2 2 2 2 2 3 2 2 ...
##  $ Magnitude        : num  2.5 2 2.4 2.2 2 2.3 2.2 6.2 2 2.2 ...
##  $ MagAuthor        : Factor w/ 1 level "--": 1 1 1 1 1 1 1 1 1 1 ...
##  $ EventLocationName: Factor w/ 45 levels "1 km NE Monte Cavallo (MC)",..: 24 36 32 45 32 41 26 44 28 9 ...

• Dataset contains data for places outside Italy and the surrounding sea

subset(df, !(Longitude>=6.0 & Longitude<=18.5 & 
            Latitude>=35.0 & Latitude<=48.0), 
            select=c('Latitude','Longitude','EventLocationName'))

##    Latitude Longitude            EventLocationName
## 8  -18.4570 -69.72400 Northern Chile [Land: Chile]
## 13 -54.0352   8.26823              Bouvet I. [Sea]

• These observations are filtered out

df <- subset(df, Latitude < 0)

• Use plotly to make a scatter plot of Lat. vs Long
• Color associated to the depth (Km) of the earthquake
• Size of each point proportional to the intensity

library(plotly)
with(df, plot_ly(x = Longitude, y = Latitude, 
                 type="scatter", mode="markers", 
                 color = ~Depth.Km, size=Magnitude) %>% 
                 layout(title = "Earthquakes Around Italy", 
                        xaxis = list(title="Longitude"), 
                        yaxis = list(title = "Latitude")))