---
title: La Palma Earthquakes
author:
  - name: Steve Purves
    orcid: 0000-0002-0760-5497
    corresponding: true
    email: steve@curvenote.com
    roles:
      - Investigation
      - Project administration
      - Software
      - Visualization
    affiliations:
      - Curvenote
  - name: Rowan Cockett
    orcid: 0000-0002-7859-8394
    corresponding: false
    roles: []
    affiliations:
      - Curvenote
keywords:
  - La Palma
  - Earthquakes
abstract: |
  In September 2021, a significant jump in seismic activity on the island of La Palma (Canary Islands, Spain) signaled the start of a volcanic crisis that still continues at the time of writing. Earthquake data is continually collected and published by the Instituto Geográphico Nacional (IGN). ...
plain-language-summary: |
  Earthquake data for the island of La Palma from the September 2021 eruption is found ...
key-points:
  - A web scraping script was developed to pull data from the Instituto Geogràphico Nacional into a machine-readable form for analysis
  - Earthquake events on La Palma are consistent with the presence of both mantle and crustal reservoirs.
date: last-modified
bibliography: references.bib
citation:
  container-title: Earth and Space Science
number-sections: true
jupyter: python3
---

## Introduction

```{python}
import matplotlib.pyplot as plt
import numpy as np
eruptions = [1492, 1585, 1646, 1677, 1712, 1949, 1971, 2021]
```

```{python}
#| label: fig-timeline
#| fig-cap: Timeline of recent earthquakes on La Palma
#| fig-alt: An event plot of the years of the last 8 eruptions on La Palma.

plt.figure(figsize=(6, 1))
plt.eventplot(eruptions, lineoffsets=0, linelengths=0.1, color='black')
plt.gca().axes.get_yaxis().set_visible(False)
plt.ylabel('')
plt.show()
```

```{python}
#| output: false

avg_years_between_eruptions = np.mean(np.diff(eruptions[:-1]))
avg_years_between_eruptions
```

Based on data up to and including 1971, eruptions on La Palma happen every 79.8 years on average.

Studies of the magma systems feeding the volcano, such as @marrero2019, have proposed that there are two main magma reservoirs feeding the Cumbre Vieja volcano; one in the mantle (30-40km depth) which charges and in turn feeds a shallower crustal reservoir (10-20km depth).

Eight eruptions have been recorded since the late 1400s (@fig-timeline).

Data and methods are discussed in @sec-data-methods.

Let $x$ denote the number of eruptions in a year. Then, $x$ can be modeled by a Poisson distribution

$$
p(x) = \frac{e^{-\lambda} \lambda^{x}}{x !}
$$ {#eq-poisson}

where $\lambda$ is the rate of eruptions per year. Using @eq-poisson, the probability of an eruption in the next $t$ years can be calculated.

| Name                | Year |
|---------------------|------|
| Current             | 2021 |
| Teneguía            | 1971 |
| Nambroque           | 1949 |
| El Charco           | 1712 |
| Volcán San Antonio  | 1677 |
| Volcán San Martin   | 1646 |
| Tajuya near El Paso | 1585 |
| Montaña Quemada     | 1492 |

: Recent historic eruptions on La Palma {#tbl-history}

@tbl-history summarises the eruptions recorded since the colonization of the islands by Europeans in the late 1400s.

![Map of La Palma](images/la-palma-map.png){#fig-map}

La Palma is one of the west most islands in the Volcanic Archipelago of the Canary Islands (@fig-map).

{{< embed notebooks/data-screening.qmd#fig-spatial-plot >}}

@fig-spatial-plot shows the location of recent Earthquakes on La Palma.

## Data & Methods {#sec-data-methods}

## Conclusion

## References {.unnumbered}

::: {#refs}
:::