page_title: 774–775 carbon-14 spike
hierarchical_section_title: 774–775 carbon-14 spike
caption_attribution_description: English: The colored dots with error bars show the C-14 data measured in Japanese (M12) and German (Oak) trees along with the typical profile for the instant production of C-14 (the black curve). Modified after [1].
context_page_description: The 774–775 carbon-14 spike is an observed increase of 1.2% in the concentration of carbon-14 isotope in tree rings dated to 774 or 775, which is about 20 times as high as the normal background rate of variation. It was discovered during a study of Japanese cedar trees, with the year of occurrence determined through dendrochronology. A surge in beryllium isotope ¹⁰
  Be, detected in Antarctic ice cores, has also been associated with the 774–775 event. It is known as the Miyake event and it produced the largest and most rapid rise in carbon-14 ever recorded.
  The event appears to have been global, with the same carbon-14 signal found in tree rings from Germany, Russia, the United States, and New Zealand.
  The signal exhibits a sharp increase of around 1.2% followed by a slow decline, which is typical for an instant production of carbon-14 in the atmosphere, indicating that the event was short in duration. The globally averaged production of carbon-14 for this event is calculated as Q = 1.3×10⁸ ± 0.2×10⁸ atoms/cm².
context_section_description: The 774–775 carbon-14 spike is an observed increase of 1.2% in the concentration of carbon-14 isotope in tree rings dated to 774 or 775, which is about 20 times as high as the normal background rate of variation. It was discovered during a study of Japanese cedar trees, with the year of occurrence determined through dendrochronology. A surge in beryllium isotope ¹⁰
  Be, detected in Antarctic ice cores, has also been associated with the 774–775 event. It is known as the Miyake event and it produced the largest and most rapid rise in carbon-14 ever recorded. 
  The event appears to have been global, with the same carbon-14 signal found in tree rings from Germany, Russia, the United States, and New Zealand.
  The signal exhibits a sharp increase of around 1.2% followed by a slow decline (see Figure 1), which is typical for an instant production of carbon-14 in the atmosphere, indicating that the event was short in duration. The globally averaged production of carbon-14 for this event is calculated as Q = 1.3×10⁸ ± 0.2×10⁸ atoms/cm².
caption: The time profile of the carbon-14 spike around 774. The colored dots represent the measurements in Japanese (M12) and German (Oak) trees, while the black lines represent the modeled profile corresponding to the instant production of carbon-14.[2]
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