This code demonstrates the use of the the USGS M2.5+ 30 day feed, and downloading the most #recent version of the event entered by the user.

getevent.py

#!/usr/bin/env python

#stdlib imports
import urllib2
import json
import sys
import os.path
import zipfile
import StringIO

#This code demonstrates the use of the the USGS M2.5+ 30 day feed, and downloading the most
#recent version of the event entered by the user.  If using this code snippet in another 
#context (say ArcGIS), then the __main__ entry point,print statements, and output file location
#should probably be replaced with whatever is appropriate.

#These feeds are found on this page:
#http://earthquake.usgs.gov/earthquakes/feed/v1.0/geojson.php

FEEDURL = 'http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_month.geojson' #30 day M2.5+
#FEEDURL = 'http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/1.0_month.geojson' #30 day M1.0+

#Get the list of event IDs in the current feed
def geteEventList():
    fh = urllib2.urlopen(FEEDURL) #open a URL connection to the event feed.
    data = fh.read() #read all of the data from that URL into a string
    fh.close()
    jdict = json.loads(data) #Parse that data using the stdlib json module.  This turns into a Python dictionary.
    eventlist = []
    for earthquake in jdict['features']: #jdict['features'] is the list of events
        if earthquake['id'] not in eventlist:
            eventlist.append(earthquake['id'])
    return eventlist

#In ArcGIS, you would call this function with an event ID (presumably) chosen from a list,
#or entered into a text box.
def main(eventid):
    fh = urllib2.urlopen(FEEDURL) #open a URL connection to the event feed.
    data = fh.read() #read all of the data from that URL into a string
    fh.close()
    jdict = json.loads(data) #Parse that data using the stdlib json module.  This turns into a Python dictionary.
    for earthquake in jdict['features']: #jdict['features'] is the list of events
        if earthquake['id'] == eventid:
            eventurl = earthquake['properties']['detail'] #get the event-specific URL
            fh = urllib2.urlopen(eventurl)
            data = fh.read() #read event data into a string
            fh.close()
            jdict2 = json.loads(data) #and parse using json module as before
            if 'shakemap' not in jdict2['properties']['products'].keys():
                print 'Event %s does not have a ShakeMap product associated with it. Exiting.'
                sys.exit(1)
            shakemap = jdict2['properties']['products']['shakemap'][0] #get the first shakemap associated with the event
            shapezipurl = shakemap['contents']['download/shape.zip']['url'] #get the download url for the shape zipfile.

            #Here, read the binary zipfile into a string
            fh = urllib2.urlopen(shapezipurl)
            data = fh.read()
            fh.close()

            #Create a StringIO object, which behaves like a file
            stringbuf = StringIO.StringIO(data)
            eventdir = os.path.join(os.getcwd(),eventid)
            if not os.path.isdir(eventdir):
                os.mkdir(eventdir)

            #Create a ZipFile object, instantiated with our file-like StringIO object.
            #Extract all of the data from that StringIO object into files in the provided output directory.
            myzip = zipfile.ZipFile(stringbuf,'r',zipfile.ZIP_DEFLATED)
            myzip.extractall(eventdir)
            myzip.close()
            stringbuf.close()
            
            filelist = os.listdir(eventdir)
            print 'Extracted %i ShakeMap files to %s' % (len(filelist),eventdir)
            sys.exit(0)
            
            

#This section is the "entry point" of the script when called from the command line
if __name__ == '__main__':
    if len(sys.argv) == 1:
        print 'Enter the id (i.e., nc72282711). Exiting.'
        sys.exit(1)
    eventid = sys.argv[1] #Grab the second item from the command line arguments (first is always name of script)
    main(eventid) #call the main function defined above

https://gist.github.com/mhearne-usgs/6b040c0b423b7d03f4b9#file-getevent-py-L43

Event detail URLs have changed, and the GeoJSON detail URL is now in the detail property:
eventurl = earthquake['properties']['detail']