A powerful earthquake measuring 5.2 on the Richter Scale struck New Zealand s second largest city Christchurch on Friday evening, halting rebuilding following previous temblors and causing hundreds of panicked shoppers to leave department stores and take to the streets.  The recent temblor struck at about 2:45pm (local time) and was centered about 27 kilometers (17 miles) east of Christchurch, according to the United States Geological Survey.  Reports said that the city also experienced an aftershock of 3.5 magnitude just four minutes after the first quake.  Although the quake was the strongest to hit the region in weeks, there were no immediate reports of damages or casualties.  Nonetheless, authorities closed down the downtown part of the city after the quake and asked hundreds of construction workers to leave the area as a precaution.  The Daily Telegraph writes that Friday s earthquake was the 41st quake in Christchurch of magnitude 5 or above since September 4, 2010.  The paper added that the New Zealand city has been rocked by hundreds of earthquakes since a magnitude-6.1 in February 2011 killed nearly 200 people and destroyed much of the central business district, making large areas of surrounding suburbs uninhabitable.