Aurora occurs when solar particles collide with Earth's atmosphere at 45 million mph. Earth's magnetic field redirects particles to poles. Particles excite gas atoms and molecules, releasing photons
Earthquake intensity differs from magnitude, which measures seismic wave amplitude. Intensity scales were developed in late 19th-early 20th centuries before seismographs. Intensity depends on ground accelerations, seismic wave features, and local structure
Seismograph records seismic waves caused by earthquakes and other shaking. Instrument uses electromagnetic sensors to convert ground motions to electrical changes. Seismogram is the recorded output of a seismograph
Charles Richter and Beno Gutenberg developed the scale in 1935. Scale measures earthquake strength using logarithmic amplitude measurements. Each whole number increase represents tenfold increase in amplitude. Magnitude 0 corresponds to 1 micron maximum amplitude at 100 km
Magnitude 7.8 earthquake struck Fairweather Fault on July 9, 1958. 30 million cubic meters of rock fell into Gilbert Inlet. Impact was heard 80 kilometers away. Maximum wave height reached 524 meters at Gilbert Inlet entrance
Lightning strikes can cause direct strikes, side splash, contact injury, or ground current. Lightning strikes have extremely high voltage of about 30 million volts. Lightning burns form unique tree-like lesions called Lichtenberg figures