*Communication* **Earth Tides and H 2 Venting in the Sao Francisco Basin, Brazil**

### **Jacob Simon 1, Patrick Fulton 1, Alain Prinzhofer 2 and Lawrence Cathles 1,\***


 **\*** Correspondence: lmc19@cornell.edu

Received: 29 September 2020; Accepted: 14 October 2020; Published: 19 October 2020

**Abstract:** Hydrogen gas seeping from Proterozoic basins worldwide is a potential non-carbon energy resource, and the vents are consequently receiving research attention. A curious feature of H2 venting in the Sao Francisco Basin in Brazil is that the venting displays a very regular daily cycle. It has been shown that atmospheric pressure tides could explain this cycle, but solid earth tides might be an alternative explanation. We show here that it is unlikely that solid earth tides are a dominant control because they have two equally strong peaks per day whereas the H2 venting has only one.

**Keywords:** diurnal hydrogen gas venting; earth tides
