R Graphical Manual

Browse All

Last data update: 2014.03.03

R: Create an Earthquake Catalog

catalog

R Documentation

Create an Earthquake Catalog

Description

Creates an object of class "catalog" representing an earthquake catalog dataset. An earthquake catalog is a chronologically ordered list of time, epicenter and magnitude of all recorded earthquakes in geographical region during a specific time period.

Usage

  catalog(data, time.begin=NULL, study.start=NULL,
          study.end=NULL, study.length=NULL,
          lat.range=NULL, long.range=NULL,
          region.poly=NULL, mag.threshold=NULL,
          flatmap=TRUE, tz="GMT")

Arguments

`data`	A `data.frame` contaning date, time, latitude, longitude and magnitude of earthquakes.
`time.begin`	The beginning of time span of the catalog. A character string or an object that can be converted to date-time (calendar dates plus time to the nearest second) by `as.POSIXlt`. The default `NULL` sets it to the date-time of the first event.
`study.start`	The start of the study period. A character string or an object that can be converted to date-time by `as.POSIXlt`. If not specified (`NULL`), then `time.begin` is used.
`study.end`	The end of the study period. A character string or an object that can be converted to date-time by `as.POSIXlt`. The default `NULL` sets it to the date-time of the last event.
`study.length`	A single numeric value specifying the length of the study period in decimal days. Incompatible with `study.end`: either `study.end` or `study.length` can be specified, but not both.
`lat.range`	The latitude range of a rectangular study region. A numeric vector of size 2 giving (latmin, latmax). By default (`NULL`) the range of the latitudes of events is used.
`long.range`	The longitude range of a rectangular study region. A numeric vector of size 2 giving (longmin, longmax). By default (`NULL`) the range of the longitudes of events is used.
`region.poly`	Polygonal boundary of a non-rectangular study region. A list with components lat and long of equal length specifying the coordinates of the vertices of a polygonal study region. The vertices must be listed in anticlockwise order.
`mag.threshold`	The magnitude threshold of the catalog. A positive numeric value. The default (`NULL`) sets it to the minimum magnitude of all events.
`flatmap`	Logical flag indicating whether to adjust the longitudes of events and the study region in order to have a flat map coordinates.
`tz`	A character string specifying the time zone to be used for the date-time conversion in `as.POSIXlt`. The default `"GMT"` is the UTC (Universal Time, Coordinated).

Details

The data is required to have at least 5 columns with names date, time, lat, long and mag containing, respectively, the date, time, latitude, longitude and magnitude of each event in the catalog.

The geographical study region can be rectangular or polygonal:

rectangular study region can be specified by lat.range and long.range which must be numeric vectors of length 2.
polygonal study region can be specified by region.poly which containst coordinates of the vertices of the polygon. It must be eighter a list with components lat and long of equal length or a data.frame with columns lat and long. The vertices must be listed in anticlockwise order and no vertex should be repeated (i.e. do not repeat the first vertex).

The function inside.owin in the spatstat is used to indicate whether events lie inside the study region. Only events inside the study region and the study period (study.start, study.end) are considered as target events. Other events are assumed to be complementary events.

If the events in data are not chronologically sorted, then a warning will be produced and the events will be sorted in ascending order with respect to time of occurrence.

If flatmap=TRUE, longitude-latitude coordinates convert to flat map coordinates. The algorithm does not change the latitude of points but adjust the longitude of points with respect to the centroid of the target geographical region in order to get coordinates on a flat surface.

Value

An object of class "catalog" containing an earthquake catalog dataset.

Author(s)

Abdollah Jalilian jalilian@razi.ac.ir

References

Zhuang, J. (2012). Long-term earthquake forecasts based on the epidemic-type aftershock sequence (ETAS) model for short-term clustering. Research in Geophysics, 2(1), 8.

Examples

  data(iran.quakes)
  summary(iran.quakes)

  # creating a catalog with rectangular study region
  iran.cat <- catalog(iran.quakes, time.begin="1973/01/01",
     study.start="1985/01/01", study.end="2016/01/01",
     lat.range=c(25, 42), long.range=c(42, 63), mag.threshold=4.5)

  print(iran.cat)
  ## Not run: 
  plot(iran.cat)
  
## End(Not run)

  # equivalently, specifying the length of the study period
  iran.cat2 <- catalog(iran.quakes, time.begin="1973/01/01",
     study.start="1985/01/01", study.length=11322,
     lat.range=c(25, 42), long.range=c(42, 63), mag.threshold=4.5)

  print(iran.cat2)



  data(jap.quakes)
  summary(jap.quakes)

  # specifying a polygonal geographical region
  jpoly <- list(long=c(134.0, 137.9, 143.1, 144.9, 147.8,
      137.8, 137.4, 135.1, 130.6), lat=c(31.9, 33.0, 33.2,
      35.2, 41.3, 44.2, 40.2, 38.0, 35.4))
  # creating a catalog with polygonal study region
  jap.cat <- catalog(jap.quakes, time.begin="1966-01-01",
      study.start="1970-01-01", study.end="2010-01-01",
      region.poly=jpoly, mag.threshold=4.5)

  print(jap.cat)
  ## Not run: 
  plot(jap.cat)
  
## End(Not run)

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(ETAS)
Loading required package: maps

 # maps v3.1: updated 'world': all lakes moved to separate new #
 # 'lakes' database. Type '?world' or 'news(package="maps")'.  #


> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/ETAS/catalog.Rd_%03d_medium.png", width=480, height=480)
> ### Name: catalog
> ### Title: Create an Earthquake Catalog
> ### Aliases: catalog
> ### Keywords: spatial math earthquake modeling
> 
> ### ** Examples
> 
>   data(iran.quakes)
>   summary(iran.quakes)
         date               time           long            lat       
 2014-08-18:  44   00:04:50.70:   2   Min.   :40.01   Min.   :22.13  
 2011-10-23:  42   04:46:33.00:   2   1st Qu.:48.34   1st Qu.:28.32  
 2013-04-09:  31   07:02:27.00:   2   Median :51.88   Median :32.13  
 2013-05-11:  27   00:00:19.42:   1   Mean   :52.20   Mean   :32.80  
 2011-10-24:  19   00:00:41.44:   1   3rd Qu.:56.39   3rd Qu.:37.52  
 1990-06-21:  18   00:00:46.52:   1   Max.   :65.00   Max.   :41.98  
 (Other)   :5789   (Other)    :5961                                  
      mag       
 Min.   :4.000  
 1st Qu.:4.200  
 Median :4.400  
 Mean   :4.468  
 3rd Qu.:4.700  
 Max.   :6.200  
                
> 
>   # creating a catalog with rectangular study region
>   iran.cat <- catalog(iran.quakes, time.begin="1973/01/01",
+      study.start="1985/01/01", study.end="2016/01/01",
+      lat.range=c(25, 42), long.range=c(42, 63), mag.threshold=4.5)
> 
>   print(iran.cat)
earthquake catalog:
  time begin 1973-01-01 
  study period: 1985-01-01  to  2016-01-01 (T = 11322 days)
geographical region:
    rectangular = [ 42 , 63 ] x [ 25 25 ]
threshold magnitude: 4.5
number of events:
  total events 2959 : 1932 target events,  1027 complementary events
  ( 111 events outside geographical region, 916 events outside study period)>   ## Not run: 
> ##D   plot(iran.cat)
> ##D   
> ## End(Not run)
> 
>   # equivalently, specifying the length of the study period
>   iran.cat2 <- catalog(iran.quakes, time.begin="1973/01/01",
+      study.start="1985/01/01", study.length=11322,
+      lat.range=c(25, 42), long.range=c(42, 63), mag.threshold=4.5)
> 
>   print(iran.cat2)
earthquake catalog:
  time begin 1973-01-01 
  study period: 1985-01-01  to  2016-01-01 (T = 11322 days)
geographical region:
    rectangular = [ 42 , 63 ] x [ 25 25 ]
threshold magnitude: 4.5
number of events:
  total events 2959 : 1932 target events,  1027 complementary events
  ( 111 events outside geographical region, 916 events outside study period)> 
> 
> 
>   data(jap.quakes)
>   summary(jap.quakes)
         date               time           lat             long      
 2011-03-11: 385   03:03:54.95:   2   Min.   :27.00   Min.   :128.0  
 2011-03-12: 187   06:45:31.21:   2   1st Qu.:34.42   1st Qu.:140.0  
 2011-03-13: 129   07:25:10.70:   2   Median :37.10   Median :141.8  
 2011-03-14:  90   10:15:33.05:   2   Mean   :36.55   Mean   :140.6  
 2011-03-15:  59   12:38:07.51:   2   3rd Qu.:39.30   3rd Qu.:142.9  
 2011-03-16:  59   15:27:59.70:   2   Max.   :44.98   Max.   :145.0  
 (Other)   :8280   (Other)    :9177                                  
      mag            depth       
 Min.   :4.500   Min.   :  0.00  
 1st Qu.:4.600   1st Qu.: 19.20  
 Median :4.800   Median : 32.00  
 Mean   :4.948   Mean   : 34.45  
 3rd Qu.:5.100   3rd Qu.: 47.70  
 Max.   :9.000   Max.   :100.00  
                                 
> 
>   # specifying a polygonal geographical region
>   jpoly <- list(long=c(134.0, 137.9, 143.1, 144.9, 147.8,
+       137.8, 137.4, 135.1, 130.6), lat=c(31.9, 33.0, 33.2,
+       35.2, 41.3, 44.2, 40.2, 38.0, 35.4))
>   # creating a catalog with polygonal study region
>   jap.cat <- catalog(jap.quakes, time.begin="1966-01-01",
+       study.start="1970-01-01", study.end="2010-01-01",
+       region.poly=jpoly, mag.threshold=4.5)
> 
>   print(jap.cat)
earthquake catalog:
  time begin 1966-01-01 
  study period: 1970-01-01  to  2010-01-01 (T = 14610 days)
geographical region:
    polygonal with vertices:
       lat  long
 [1,] 31.9 134.0
 [2,] 33.0 137.9
 [3,] 33.2 143.1
 [4,] 35.2 144.9
 [5,] 41.3 147.8
 [6,] 44.2 137.8
 [7,] 40.2 137.4
 [8,] 38.0 135.1
 [9,] 35.4 130.6
threshold magnitude: 4.5
number of events:
  total events 6032 : 4104 target events,  1928 complementary events
  ( 1265 events outside geographical region, 663 events outside study period)>   ## Not run: 
> ##D   plot(jap.cat)
> ##D   
> ## End(Not run)
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>