Azores tectonic or vulco-tectonic in nature, but in general low to medium intensities, occasionally punctuated by events of level 5 or greater on the Richter magnitude scale. The most severe earthquake was registered in 1757, near Calheta on the island of São Jorge, which exceeded 7 on the Richter magnitude scale. In comparison, the 1522 earthquake that was mentioned by historian Gaspar Frutuoso measured 6.8, but its effects were judged to be X ("Extreme") on the Mercalli intensity scale, and was responsible for the destruction of Vila Franca do Campo and landslides that may have killed more than 5,000 of the
Absolute magnitude corresponds to absolute bolometric magnitude 4.74. Placing a radiation source (e.g. star) at the standard distance of 10 parsecs, it follows that the zero point of the apparent bolometric magnitude scale corresponds to irradiance . Using the IAU 2015 scale, the nominal total solar irradiance ("solar constant") measured at 1 astronomical unit () corresponds to an apparent bolometric magnitude of the Sun of −26.832. Following Resolution B2, the relation between a star's absolute bolometric magnitude and its luminosity is no longer directly tied to the Sun's (variable) luminosity: where The new IAU absolute magnitude scale permanently disconnects the scale from