What was reported

A magnitude 3.6 earthquake struck the Pamplona region on the morning of Friday 9 October at 10:49, according to the Instituto Geográfico Nacional. Sources differ on the epicenter: most place it near Burlada, while eldiario.es names Aranguren. The tremor was felt in about thirty localities, including Pamplona, Orkoien, Ansoáin, Berriozar, Burlada, Huarte, Mutilva, Noáin, Sarriguren, Villava, Barañáin, Zizur Mayor and Olaiz. Depth is reported as 3 km by eldiario.es and El Mundo, and as 10 km by ABC, while El Confidencial gives no figure. No personal or material damage had been reported in the earliest coverage.

A smaller tremor minutes earlier

A tremor of magnitude 2.7 was recorded at 10:42 with its epicenter in the Valle de Egüés, a few minutes before the main shock. The Instituto Geográfico Nacional had not yet listed the localities where it was felt, although some residents said they had perceived it too. El Confidencial reports that two tremors had been recorded in the preceding days and five so far this month, and that the 3.6 quake was the strongest in the area in recent times, above the magnitude 1.9 recorded on 21 April this year. One early account described the intensity as low, saying only some residents of Villava, Ansoáin and Pamplona might have perceived it.

Reactions on the ground

Government president María Chivite was in Sarriguren at the Ingeteam company, greeting managers, when the tremor hit. El Mundo reports that a loud noise preceded the shaking, and Chivite herself, surprised, suggested it might be an earthquake. On social media, residents asked in WhatsApp groups whether others had felt it, while others said it had woken them, shaken the entire house or frightened them. 112 SOS Navarra said no incidents had been recorded so far, and El Confidencial notes that official confirmation was still pending.

Reporting what was felt and scale context

The macroseismic questionnaire lets anyone who felt the tremor describe what they were doing, whether they were awake, how they reacted, and whether objects moved or fell. 20 minutos explains that earthquakes happen when energy stored inside the Earth is released suddenly, sending seismic waves through the ground, and that they are often caused by tectonic plates moving along faults. El Confidencial also explains that the Richter scale is logarithmic, so a magnitude 4 quake is 100 times stronger than a magnitude 2, not twice as strong. It notes that the theoretical maximum is 12 degrees, enough to fracture the Earth's surface, and that the largest recorded earthquake reached 9.5 in Valdivia, Chile.