In XML, these two are equivalent: <foo><bar/></foo> and <foo><![CDATA[<bar/>]]></foo>. Thus the content of the <summary> tag is the "<p class="quicksummary"><a href="http://earthquake.usgs...". If you want to split that into pieces you have to pass that string to another HTML or XML parser. It's like a box that, apart from other things, contains another box so after you've opened the outer box, you have to extract the inner box and open it as well.
Enoch was right!
Enjoy the last years of Rome.