Nearby Earthquakes

Nearby Earthquakes is a program which for a given coordinates (lat/lon) provides 10 nearest earthquakes based on USGS Earthquake Hazards Program data.

Earthquakes data

It checks all earthquakes that happened during last 30 days: https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_month.geojson

Calculating distance

Currently it calculates distance using Haversine formula:

a = sin²(Δφ/2) + cos φ1 ⋅ cos φ2 ⋅ sin²(Δλ/2)
c = 2 ⋅ atan2(√a, √(1−a))
d = R ⋅ c

where φ is latitude, λ is longitude, R is earth’s radius (6,371km). Angles need to be in radians to pass to trigonometric functions.

(from R. W. Sinnott, "Virtues of the Haversine", Sky and Telescope, vol. 68, no. 2, 1984, p. 159)

Program input

Program accepts two float numbers on standard input: the latitude in [-90.0, 90.0] and the longitude in [-180.0, 180.0].

Program output

As an output program prints a list of 10 earthquakes that happened in the closest proximity to input point, in the order from the closest to the furthest. For each earthquake it prints description followed by || and distance (rounded to full kilometers).

description || distance  
description || distance  
description || distance  

Summary

• Reads two float numbers from standard input that represent the lat/lon coordinates
• Gets a list of earthquakes that happened during last 30 days
• Calculates distance between given point and each of the earthquakes
• Prints the 10 earthquakes with the shortest distance to the given point
• The output list contains earthquake title and distance in kilometers

Usage examples:

Input example:

40.730610  
-73.935242  

Output example:

M 1.3 - 2km SSE of Contoocook, New Hampshire || 331  
M 1.3 - 2km ENE of Belmont, Virginia || 354  
M 2.4 - 83km ESE of Nantucket, Massachusetts || 406  
M 1.3 - 13km ENE of Barre, Vermont || 410  
M 0.7 - 18km NW of Norfolk, New York || 476  
M 2.0 - 17km NW of Norfolk, New York || 476  
M 1.7 - 19km NNW of Beaupre, Canada || 758  
M 1.9 - 13km SW of La Malbaie, Canada || 814  
M 2.4 - 16km N of Lenoir, North Carolina || 840  
M 2.4 - 12km ESE of Carlisle, Kentucky || 896  

Configuration:

Program supports following configurations (earthquakes.properties):

• usgs.earthquakes.month.uri - URI of earthquakes data source
• usgs.earthquakes.month.nearby.limit - number of earthquakes to be printed out
• usgs.earthquakes.cache.enable - enable caching of earthquakes data
• usgs.earthquakes.cache.period - cache update period in minutes

Build:

Minimum requirements:

• Apache Maven 3.3.3
• JDK 1.8

Run from project root:

mvn clean install

Output directory ./target/releases

Run:

Instructions for running (requires JRE 1.8) you can find at readme.txt. Was tested on Windows 10, Ubuntu 15.10 and MacOS 10.14.