( CNN ) -- Confusion and then an uneasy calm . That 's how residents up and down the East Coast described their reaction to the 5.8-magnitude earthquake that rattled millions of people Tuesday . The quake , which struck at 1:51 p.m. , was shallow -- just 3.7 miles deep . The epicenter was about 40 miles northwest of Richmond , Virginia , the U.S. Geological Survey said . It sent tremors throughout the region , surprising people at least as far away as New York , Ohio and Georgia . Sarah Merz said her co-worker in Camden , New Jersey , was the first one to notice the rumbling . `` She said , 'What is that ? Is it a train ? ' Everyone kind of started looking at each other . Everyone 's eyes just kind of widened , and we all just ran to the front door . '' People stood stunned outside for a few minutes , she said . `` All of the sudden your heart starts to pound because you know on the East Coast , this just does n't happen . It made me nervous at first , but then at the same time it 's kind of this crazy curiosity . '' Even an hour after the quake , Merz , 28 , said she still felt dizzy . `` You 're like , wait , am I moving ? You keep second-guessing yourself . ... You start thinking too much . You 're like , is it happening again ? '' When she sat down at her desk , Merz noticed her framed college diploma was still vibrating on the wall . Stories like hers poured in from across the East Coast as residents , generally not used to earthquakes , struggled in the early moments of the temblor to understand what was happening . Was is a helicopter ? A truck ? A train ? Kate Duddy was in an office building elevator in Manhattan , alone , when the shaking started . `` I have never felt a quake before . It was scary having no idea what the cause was , '' she said . `` I felt the vibrations and the elevator stopped for a period of about five minutes . '' Gabby Randle , 23 , was in a meeting in an office building at New York Avenue and 15th Street in Washington . `` We could see a couple of things falling off of the building next to us , '' she said . `` We sort of ran because the ceiling tiles were swaying . '' An official who works in a federal building in New York said he thought someone was `` playing a joke '' on him when his desk started shaking . `` And then , '' he said `` I felt my whole body swaying and realized it was something much more . '' Many buildings were evacuated in the U.S. capital , where huge crowds lined the streets as police cars sped by with sirens sounding . CNN iReporter Susan Prahinski sent CNN images of her home office in Washington . The quake knocked shelves off her walls and sent books and her computer monitor crashing . A statue of the Greek philosopher Aristotle lost its head . In Spotsylvania , Virginia , Tish Walker said she grabbed her dog and raced outside when the earthquake struck . `` I used to live in California , so I know shaking and this felt big , '' she said . `` My first thought is always that the furnace might explode or a cabinet crashes down on top of us . '' Courtney Thompson , a CNN iReporter from Lanoka Harbor , New Jersey , had no doubt it was a quake , either . The question for her was whether it had occurred out in the ocean . She said everyone taking in the sun at Ortley Beach , New Jersey , sprang up at the same time and looked anxiously out to the Atlantic . `` The water did not recede ( a telltale sign of an impending tsunami ) , but I 'm sure that 's what everyone was worried about , '' she said . `` People started panicking . They did n't tell us we had to get off the beach , but I 'm telling you , everyone got right off the beach . '' Brendan Wein , a sales representative at Hoffman Nursery near Rougemont , North Carolina , said he first sensed rattling inside the building . `` We were thinking it was a helicopter , '' Wein said . `` I was literally shaking in my chair . '' Simon Griffiths , in Raleigh , North Carolina , compared the quake to a tractor-trailer truck roaring outside his house . Billy Wray said his guitars are OK , but things felt pretty weird when the bank building that houses his music shop in Mechanicsville , Pennsylvania , started to sway . `` Over here , we were rocking and rolling , '' he said . CNN iReporter Jeff Yapalater said he was in his backyard in New York 's Long Island when the shaking started . `` Suddenly I felt this light swaying of the earth , I 'd never felt that before , so I thought maybe I was experiencing vertigo for a moment , and it lasted maybe 30 seconds . ... We 're feeling this really far away ! '' he wrote . CNN 's Susan Candiotti came across a couple waiting to get back into an evacuated courthouse , where they had been waiting to be married when the quake struck . `` I did n't feel the shaking at all , '' the groom said . He glanced over to his fiancee and joked , `` Maybe it 's a sign . '' CNN 's Philip Gast , Katy Byron , Brian Walker and Susan Candiotti contributed to this report .
The quake , near Washington , sends tremors as far away as North Carolina . `` At first we thought it was a huge truck that went past , '' a witness says . `` I know shaking and this felt big , '' says a former Californian , now in Virginia . People line the streets in Washington , where many building are evacuated .