Nepal Earthquake

Nov 20, 2019 3 min read R

I wanted to analyze the data from the April 2015 Nepal earthquake that resulted in around 10,000 deaths. I am using a dataset that I found in data.world. The data contains date, time, location and magnitude of the earthquake and the many aftershocks that followed. The data is updated as of June 2, 2015.

Nepal is my birthplace, my homeland. The earthquake was an extremely traumatic event for people who live there. Many people lost family members, their houses. I visited Nepal in 2017 and saw that every other house in Patan, Nepal (close to Kathmandu) was damaged. My relatives would talk about their experience of the earthquakes every day.

Libraries

library(tidyverse)
library(geojsonio)
library(broom)
library(gganimate)
library(leaflet)
library(widgetframe)

Read in the data and clean

earthquake_dat <- read_csv("https://raw.githubusercontent.com/meghapsimatrix/Data_Visualization/master/data/earthquake-0-csv-1.csv") %>%
  mutate(lab = paste0(Epicentre, "; ", Date,"; Magnitude(ML): ", `Magnitude(ML)`))

head(earthquake_dat)

## # A tibble: 6 x 7
##   Date       `Local Time` Latitude Longitude `Magnitude(ML)` Epicentre  lab     
##   <date>     <time>          <dbl>     <dbl>           <dbl> <chr>      <chr>   
## 1 2015-06-01 04:35            28.0      85.5             4   Sindhupal… Sindhup…
## 2 2015-05-31 13:54            28.3      84.5             4.2 Lamjung    Lamjung…
## 3 2015-05-30 22:13            27.8      85.2             4.5 Nuwakot    Nuwakot…
## 4 2015-05-30 20:35            28.0      85.2             4   Rasuwa/Nu… Rasuwa/…
## 5 2015-05-30 01:52            27.8      85.2             4   Dhading /… Dhading…
## 6 2015-05-29 15:44            28        85.0             5.2 Dhading    Dhading…

# there is one entry where I think the lat and long are switched
summary(earthquake_dat$Latitude)

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   26.94   27.71   27.82   28.06   27.98   84.71

summary(earthquake_dat$Longitude)

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   28.16   85.23   85.80   85.25   86.06   86.67

# Gorkha seems like the lat and long are switched
(outlier <- earthquake_dat %>%
  filter(Latitude == max(Latitude)))

## # A tibble: 1 x 7
##   Date       `Local Time` Latitude Longitude `Magnitude(ML)` Epicentre lab      
##   <date>     <time>          <dbl>     <dbl>           <dbl> <chr>     <chr>    
## 1 2015-04-25 18:29            84.7      28.2             5.5 Gorkha    Gorkha; …

earthquake_dat <- earthquake_dat %>%
  mutate(Latitude = if_else(lab == outlier$lab & Date == outlier$Date, outlier$Longitude, Latitude),
         Longitude = if_else(lab == outlier$lab & Date == outlier$Date, outlier$Latitude, Longitude))

# Sindhupalchowk seems like the Longitude is wrong
earthquake_dat %>%
  filter(Longitude == min(Longitude))

## # A tibble: 1 x 7
##   Date       `Local Time` Latitude Longitude `Magnitude(ML)` Epicentre  lab     
##   <date>     <time>          <dbl>     <dbl>           <dbl> <chr>      <chr>   
## 1 2015-05-08 08:19            27.8      28.9             4.2 Sindhupal… Sindhup…

sindhupalchowk <- earthquake_dat %>%
  filter(str_detect(Epicentre, "Sindhu"))

# Mean imputing based on other values for Sindhupalchowk
earthquake_dat <- earthquake_dat %>%
  mutate(Longitude = if_else(Longitude == min(Longitude), mean(sindhupalchowk$Longitude), Longitude))

Make a Map of Nepal

I got the code for the base map from here.

np <- geojson_read("https://raw.githubusercontent.com/mesaugat/geoJSON-Nepal/master/nepal-districts.geojson",  what = "sp")
np_dat <- tidy(np)


# plot
np_plot <- ggplot() +
  geom_polygon(data = np_dat, aes( x = long, y = lat, group = group)) 

np_plot

Mapping on the Earthquake and Aftershocks

Now plotting the latitude and longitudes. Size indicates the magnitude of the earthquake.

(np_earthquake <- np_plot + 
  geom_point(data = earthquake_dat, 
             aes(x = Longitude, y = Latitude, 
                 size = `Magnitude(ML)`), 
             color = "red", alpha = .5) + 
  labs(color = "") + 
  theme_void() +
  theme(legend.position = "none"))

Animating

np_animate <- np_earthquake +
  transition_states(Date) +
  labs(title = 'Date: {closest_state}') +
  enter_appear() +
  exit_disappear()

animate(np_animate)

Leaflet

Created using the leaflet package. Click on the dots on the map to learn the location, date, and the magnitude of the earthquake or aftershock.

np_leaf <- leaflet(earthquake_dat) %>% 
  setView(lat = 27, lng = 85, zoom = 7) %>%
  addProviderTiles(providers$CartoDB.DarkMatter) %>%
  addCircleMarkers(~Longitude, ~Latitude,
                   radius = ~`Magnitude(ML)`, fillOpacity = 0.5,
                   popup = ~lab, stroke = FALSE)

frameWidget(np_leaf)

Nepal Nepal Earthquake 2015 gganimate ggplot leaflet