head(quakes)
##      lat   long depth mag stations
## 1 -20.42 181.62   562 4.8       41
## 2 -20.62 181.03   650 4.2       15
## 3 -26.00 184.10    42 5.4       43
## 4 -17.97 181.66   626 4.1       19
## 5 -20.42 181.96   649 4.0       11
## 6 -19.68 184.31   195 4.0       12
head(quakes[,1:0])
## [1] -20.42 -20.62 -26.00 -17.97 -20.42 -19.68
head(quakes[,2:2])
## [1] 181.62 181.03 184.10 181.66 181.96 184.31
library(leaflet)

leaflet() %>%     # Inicialización
  addTiles() %>%  # Añadir mapa.
  addMarkers(lng = as.numeric(as.character(quakes$long)),
             lat = as.numeric(as.character(quakes$lat)),
             clusterOptions = markerClusterOptions() # Agrupar al alejar 
             )