![]() So there you have it - while these earthquakes were near Lassen, there's no danger of eruption. We've seen no evidence of that at Lassen recently: no earthquake swarms, no ground swelling, and no change in the gases coming out of the volcano. The short answer is no! While some eruptions might be triggered by large earthquakes, it only seems to happen when the volcano is already primed and ready to erupt - that is, there already needs to be gassy magma near the surface. A similar earthquake sequence happened there in May of 2013 ( ).įinally, many of you asked if these earthquakes could affect Lassen. The area contains several N-S and NW-SE trending fault zones, including the Lake Almanor fault, which are active and prone to earthquakes. Lake Almanor falls roughly within the Basin and Range, and its tectonic history is very different from Lassen's. But only a few miles to the east are the Modoc Plateau and Basin and Range provinces. The Lassen Volcanic Center is at the southern end of the Cascades Volcanic Arc, formed by a subduction zone. It was hailed as the biggest test yet of the warning system since its public launch. As sensors picked up the first signs of a strong earthquake jolting the Northern California coast, an alert was blasted to 3 million smartphone users telling them to drop, cover, hold on. ![]() Our next clue is that Lake Almanor is not in the same physiographic province (defined by tectonics, landforms, and volcanism) as Lassen. California earthquake puts early warning system to the test. Volcanic earthquakes also follow a more complicated pattern than mainshock-aftershock sequences ( ) At a volcano, we would expect seismicity to have widely varying focal mechanisms, depending on earthquake location. Focal mechanisms (a way of describing the type of slip) tell us that these earthquakes occurred on a normal fault. To start, the distance and character of these earthquakes tell us that they're unlikely to have anything to do with Lassen. ![]() Because Lake Almanor is close to Lassen, CalVO received many questions about potential connections to the volcano. The initial M5.5 earthquake ( ) was followed by a M5.2 quake ( ) as well as dozens of smaller aftershocks. The earthquakes are associated with normal Basin and Range province faulting, and there are numerous fault zones under and around the lake which could be the source of the sequence. This map shows the locations of two M5+ earthquakes and numerous aftershocks in and around Lake Almanor, CA, from 11.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |