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The subject of our study is the possible relationships between the state of the lower ionosphere and tectonic events on Earth during episodes of high solar activity. There is evidence that during such episodes, electrical interactions between the lower ionosphere (layers D and E), the Earth's surface, and the lithosphere can play an important role in triggering seismic or volcanic events, if the geological objects involved are close to the near-critical state. As examples, we consider three strong earthquakes that occurred during solar cycle 24 (SC24 according to the Zurich classification) and the possibility of their initiation by strong solar flares and related events (sudden ionospheric disturbances, SIDs): 1. The Mexican earthquake (M = 8.1) on September 7–8, 2017; 2. The Chilean earthquake (M = 8.1) of April 1, 2014, and 3. The Japanese earthquake of November 3, 2011. The possibility of using indirect data to study solar flare–ionospheric triggers of large earthquakes that occurred after 1874 A.D. is discussed. This indirect information refers to the areas of sunspot groups, their morphology types, and apparent locations on the solar disk for the corresponding dates. The Chirpan earthquake of April 14, 1928 is given as an example. The inverse piezoelectric effect is one of the most possible physical mechanisms to explain the identified patterns. The possibility of using SID monitor (VLF) data to study these phenomena is briefly discussed. [ABSTRACT FROM AUTHOR]